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ANATOMY  AND   PHYSIOLOGY 

FOR   NURSES 


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THE  MACMILLAN  COMPANY 

NEW  YORK    •    BOSTON   •    CHICAGO        DALLAS 
ATLANTA   •    SAN   FRANCISCO 

MACMILLAN  &  CO.,  Limited 

LONDON  •  BOMBAY  •  CALCUTTA 
MELBOURNE 

THE  MACMILLAN  CO.  OF  CANADA,  Ltd. 

TORONTO 


TEXT-BOOK 


OF 


Anatomy  and  Physiology 


FOR   NURSES 


COMPILED    BY 

DIANA  CLIFFORD   KIMBER 

Geaduatb  of  Bellev0b  Training  School;  formerly  Assistant  Sitpeeintendent  New 

YoEK  CiTV  Training  School  for  Nurses,  Blaokwell's  Island,  N.Y.  ;  formerly 

Assistant  Superintendent  Illinois  Training  School,  Chicago,  III. 


FOURTH    EDITION,    COMPLETELY    REVISED,    WITH    ADDITIONS 

AND    MANY    NEW    ILLUSTRATIONS 

BY 

CAROLYN   E.   GRAY,   R.N. 

Superintendent  of  City    Hospital    School    op    Nursing,  formerly    New  York  City 
Training  School  for  Nurses 


THE   MACMILLAN   COMPANY 

1916 

All  riff /its  reserved 


COPYBIGHT,    1898, 

By  MACMILLAN  AND  OO. 

CoPTKiGHT,  1902,  1909,  1914, 
Bt  the   MACMILLAN  COMPANY, 


Set  up  and  electrotyped.  Published  September,  1894.  Reprinted  November, 
1894;  February,  August,  1895;  January,  November,  1896;  Julv,  December, 
1897;  September,  1898  ;  July,  1899;  February,  October,  1900  ;   March,  1 901. 

New  edition,  revised,  printed  February,  October,  1902  ;  February,  October, 
^903  ;  June,  1904  ;  January,  October,  1905  ;  January,  1906  ;  January,  CJctober, 
1907  ;  January,  July,  1908. 

New,  and  completely  revised  edition,  published  September,  1909.  Reprinted 
October,  1909  ;  August,  1910;  March,  November,  191 1  :  August,  1912  ; 
March,  1913 

New  edition,  completely  revised.  September,  1914  ;  January,  August, 
October,  X91S;  January,  July,  December,  1916. 


J.  8.  Cashing  Co.  —  Berwick  &,  Smith  Oo. 
Norwood,  Mass.,  U.S.A. 


Affectionate Ig  lietiicatetj 

TO   MY 
FRIEND,   SCHOOLMATE,   AND   SUPERINTENDENT 

%onm  ©arrfje 

GRADUATE   OF   BELLEVUE   TRAINING   SCHOOL 

AND 

SUPERINTENDENT  NEW  YORK   CITY   TRAINING   SCHOOL 

BLACKWELL'S   ISLAND,  N.Y. 


PREFACE 

Once  more  this  book  has  been  thoroughly  revised.  This 
revision  represents  an  effort  to  simplify  the  most  difficult 
portions,  to  introduce  more  physiology,  and  to  present  more 
fully  the  subject  of  the  generative  organs.  Much  of  the  book 
has  been  rewritten,  a  number  of  new  illustrations  have  been 
introduced,  and  several  that  seemed  to  have  outlived  their 
usefulness  have  been  discarded. 

As  in  the  previous  revision,  many  Superintendents  and 
Teachers  of  Training  Schools  have  been  consulted  both 
personally  and  by  letter.  The  suggestions  offered  by  them 
have  been  of  very  great  value,  and  have  been  carried  out  as 
far  as  possible.  It  is  a  privilege  and  pleasure  to  acknowledge 
this  indebtedness. 

My  thanks  are  due  to  Miss  Charlotte  A.  Francis,  Instructor 
of  Chemistry  in  Teachers  College,  Columbia  University,  for 
rewriting  the  first  chapter,  also  to  Dr.  R.  J.  E.  Scott  of  New 
York,  who  supervised  the  entire  revision  and  made  the  index. 

I  am  also  indebted  to  the  authors  whose  works  I  have  con- 
sulted, and  to  the  various  publishers  who  have  granted  me 
permission  to  use  illustrations  from  their  books. 

Miss  Kimber,  while  not  actively  engaged  in  Training  School 

work,  is  still  keenly  interested  in  all  that  pertains  to  nursing 

progress,  and  derives  much  satisfaction  from  the  thought  that 

her  text-book  is  of  real  service  to  nurses.     That  its  service  and 

usefulness  may  be  increased  by  the  present  edition  is  the  sincere 

wish  of  the  reviser. 

C.  E.  G. 


TABLE   OF   CONTENTS 

OBAPTSR  PAGB 

I.     Explanations  and  Definitions  of  Some  Chemical  and  Physical 

Terms 3 

II.     Definitions.  —  Cavities  of  the  Body 14 

m.     Cells,  Tissues,  Organs,  and  Systems.  — Epithelial  Tissue :  Simple, 

Transitional,  Stratified 21 

IV.     Connective  Tissues  :  Areolar,  Fibrous,  Elastic,  Adipose,  Reticular, 

Lymphoid,  Cartilage,  Bone 34 

V.     The  Skeleton 49 

VI.     Articulations 82 

VII.     Muscular  Tissue  :  Classification  ;  Prominent  Skeletal  Muscles     .       89 

VIII.     Special  Membranes  and  Glands 127 

IX.     Vascular  System  ;  The  Blood  and  Lymph 141 

X.     The  Blood  Vascular  System,  and  the  Lymph  Vascular  System     .     161 
XI.     The  Vascular  System  Continued  :  Arteries  ;  Pulmonary  System  ; 
General  System ;  Veins ;  Supplementary  Channel,  and  Portal 

System 184 

XII.     The    Vascular    System    Continued :    The    General    Circulation  ; 

Blood  Pressure  ;  The  Pulse  ;  Lymph  ;  Foetal  Circulation         .     214 

XIII.  Respiratory  System  :  Nose  ;  Larynx  ;  Trachea  ;  Bronchi ;  Lungs. 

—  Respiration;   Abnormal  Types   of   Respiration.  —  Modified 
Respiratory  Movements      ........     232 

XIV.  The  Digestive  System  :  Alimentary  Canal  and  Accessory  Organs    254 
XV.     Classification  of  Food.  —  Digestive  Processes  ;  Changes  the  Food 

undergoes  in  the  Mouth,  Stomach,  Small  and  Large  Intestines  ; 

Absorption 286 

XVL     Metabolism  —  Ductless  Glands 307 

XVII.     Waste  Products :  Excretory  Organs ;  Description  of  the  Organs 
constituting  the  Urinary  System  ;  General  Characters  of  Urine  ; 
Composition  of  Urine  ........     324 

XVIII.     The  Skin  ;  Appendages  of  the  Skin.  —  Production  of  Heat ;  Reg- 
ulation of  Heat.    Variations  in  Temperature      ....     344 

XIX.     The  Nervous  System 363 

XX.     Internal  and  External  Senses:  Taste,  Smell,  Hearing,  and  Sight    408 
XXI.     The  Organs  of  Generation  :  Physiology  of  Reproduction    .        .     442 

Glossary 471 

Index 605 


LIST   OF   ILLUSTRATIONS 

TIG,  PAGE 

1.  Front  view  of  a  man  in  the  anatomical  position.     (Gerrish)         .        .  15 

2.  Back  view  of  a  man.     (Gerrish)   . .16 

3.  Diagrammatic  longitudinal  section  of  the  trunk  and  head    ...  17 

4.  Position  of  the  thoracic  and  abdominal  organs  (front  view).    (Morrow)  18 

5.  Position  of  the  thoracic  and  abdominal  organs  (rear  view).     (Morrow)  19 

6.  Diagram  of  a  cell.     (Wilson) 22 

7.  Diagrams  illustrating  division  of  a  cell.     (Bigelow,  from  Wilson)        .  24 

8.  Diagrams  to  illustrate  fertilization  of  an  egg-cell  (ovum)  by  a  sperm- 

cell  (spermatozoon).     (Bigelow) 27 

9.  Simple  pavement  epithelium .28 

10.  Simple  columnar  epithelium  .         .         .         .     * 28 

11.  Ciliated  epithelium  from  the  human  trachea 29 

12.  Section  of  the  transitional  epithelium  lining  the  bladder.     (Schiifer)  .  29 

13.  Section  of  stratified  epithelium.     (Schafer)  ......  30 

14.  Subcutaneous  areolar  tissue  from  a  young  rabbit.     (Schafer)       .         .  35 

15.  Fibrous  tissue,  from  the  longitudinal  section  of  a  tendon.     (Gegen- 

bauer) 36 

16-.  A  few  fat  cells  from  the  margin  of  a  fat  lobule.     (Schafer)          .         .  38 

17.  Eetiform  tissue  from  a  lymph  node.     (Quain)       .....  39 

18.  Articular  hyaline  cartilage  from  the  femur  of  an  ox.     (Ranvier)         .  40 

19.  Vertical  section  of  a  long  bone.     (Gerrish) 43 

21.  The  human  skeleton.     (Morrow)  ........  50 

22.  Side  view  of  the  skull.     (Morrow) 63 

23.  Front  view  of  the  skull.     (Morrow) 54 

24.  Occipital  bone 55 

25.  Parietal  bone 56 

26.  Frontal  bone 56 

27.  The  right  temporal  bone.     (Gerrish) 57 

28.  Ethmoid  bone 57 

29.  Parietal,  temporal,  and  sphenoid  bones.     (Gould's  Dictionary)  .         .  58 

30.  Skull  of  new-born  child.     (Edgar) 59 

31.  Skull  of  new-bom  child.     (Edgar) 69 

32.  Nasal  bones.     (Gerrish) 60 

33.  Sagittal  section  of  face,  a  little  to  the  left  of  the  middle  line,  showing 

the  vomer  and  its  relations.     (Gerrish) 60 

34.  Right  inferior  turbinate  bone.     (Gerrish) 61 

35.  Lacrimal  bone .61 

36.  Right  malar  bone.     (Gerrish) 61 

37.  The  two  palate  bones  in  their  natural  position.     (Gerrish)  ...  62 

38.  The  right  maxilla.     (Gerrish) 62 

39.  The  mandible.     (Gerrish) 63 

40.  The  hyoid  bone.     (Gerrish) 63 

41.  The  vertebral  column.     (Gerrish) 64 

xi 


xu 


LIST  OF  ILLUSTRATIONS 


no. 
42. 
43. 
44. 
45. 
46. 
47. 
48. 
49. 
50. 
61. 
52. 
53. 
54. 
55. 
56. 
57. 
58. 
50. 
60. 
61. 
62. 
63. 
64. 
65. 
66. 
67. 
68. 
69. 
70. 
71. 
72. 
73. 
74. 
75. 

76. 
77. 
78. 
79. 
80. 
81. 
82. 
83. 
84. 
85. 
86. 
87. 
88. 


A  cervical  vertebra 
The  atlas.     (Gerrish)     . 
The  axis  (epistropheus). 
Thorax  .... 


(Gerrish) 


The  sternum.     (Gerrish) 

The  eighth  rib  of  the  right  side.     (Gerrish)  . 

The  right  clavicle.     (Gerrish) 

The  right  scapula,  or  shoulder  blade.     (Morrow) 

The  left  humerus,  or  arm  bone.     (Morrow) 

The  bones  of  the  right  forearm.     (Morrow) 

The  bones  of  the  right  hand.     (Gerrish) 

Development  of  the  hip  bone.     (Gerrish) 

Female  pelvis         ...... 

Male  pelvis 

Tlie  right  femur,  or  thigh  bone.     (Morrow) 

The  right  patella.     (Gerrish) 

The  bones  of  the  right  leg.     (Morrow) 

The  bones  of  the  right  foot.     (Gerrish) 

A  toothed,  or  dentated,  suture 

Diameters  and  landmarks  of  the  fatal  skull.     (Edgar) 

Diameters  and  landmarks  of  the  fcetal  skull.     (Edgar) 

A  slightly  movable  joint 

A  complete  joint    . 

Diagram  of  muscle  fibre  with  sarcolemma  attached 
Fibre-cells  of  plain  muscular  tissue        .... 
Superficial  muscles  of  head  and  neck.     (Gerrish) 
Muscles  of  right  eyeball  within  the  orbit 

Muscles  of  eyeball 

Temporal  and  deep  muscles  about  the  mouth.     (Gerrish) 

Pterygoid  muscles.     (Gerrish)       .         .         .         . 

Muscles  of  the  tongue.     (Gerrish)         .... 

The  ligamentiim  nuchse.     (Gerrish)       .... 

Muscles  in  the  superficial  layer  of  the  back.     (Gerrish) 

Front   of    chest    and    shoulder   of    right  side,    superficial    muscles 

(Gerrish) 

Intercostal  muscles  in  right  wall  of  thorax.     (Gerrish) 
Diaphragm.     (Gerrish)  ...... 

Rectus  abdominis  and  obliquus  internus  of  right  side.     (Gerrish) 
Transversalis  abdominis  of  right  side.     (Gerrish) 
Muscles  of  the  front  of  the  riglit  shoulder  and  arm.     (Gerrish) 
Mu.scles  on  the  dorsum  of  the  right  shoulder  and  arm.     (Gerri.sh) 
Muscles  in  the  dorsum  of  the  right  forearm  and  hand.     (Gerrish) 
Psoas,  iliacus,  and  obturator  extemus  muscles.     (Gerrish)  . 
Gluteus  maximus  of  right  side.     (Gerrish)    .... 

Muscles  in  the  dorsum  of  the  right  thigh.     (Gerrish)   . 
Superficial  muscles  in  front  part  of  the  right  thigh.     (Gerrish) 
Vastus  intermedins  of  right  side.     (Gerrish) 
Gastrocnemius  of  right  side.     (Gerrish)        .... 

The  anterior  annular  ligament  of  the  ankle  and  the  synovial  mem 

branes  of  the  tendons  beneath  it.     (Gerrish) 


PA08 

65 
66 
66 
67 
68 
69 
70 
70 
71 
72 
73 
74 
75 
76 
77 
77 
78 
79 
82 
83 
84 
84 
85 
90 
90 
96 
97 
97 
98 
99 
100 
102 
103 

104 
104 
106 
107 
108 
111 
111 
112 
114 
115 
116 
116 
117 
117 

130 


LIST  OF  ILLUSTRATIONS  xiii 

FIG.  PAGE 

90.  Diagram  of  the  gastro-pulmonary  mucous  membrane,  showing  the  con- 

tinuity of  all  its  parts.     (Gerrish) 131 

91.  Diagram  of  the  female  genito-urinary  mucous  membrane,  showing 

continuity  of  all  its  parts.     (Gerrish) 132 

92.  Diagram  of  the   male   genito-urinary  mucous   membrane,   showing 

continuity  of  all  its  parts.     (Gerrish) 133 

93.  An  intestinal  villus 134 

94.  Diagram  showing  development  of  glands.     (Gerrish)          .         .         .  135 

95.  Bowl  of  recently  clotted  blood,  showing  the  whole  mass  uniformly 

solidified.     (Dalton) 149 

96.  Bowl  of  clotted  blood  after  twelve  hours,  showing  the  clot  contracted 

and  floating  in  the  fluid  serum.     (Dalton) 149 

97.  Heart  in  situ.     (Dalton) 162 

98.  Anterior  view  of   heart,  dissected,  after  long  boiling,  to  show  the 

superficial  muscular  fibres.     (Quain) 162 

100.   Diagram  of  heart  and  serous  pericardium 164 

102.   Cross-section   through   both  ventricles,  showing  the  shape  of   their 

cavities  and  the  relative  thickness  of  their  walls.     (Gerrish)        .  166 

104.  Aortic  valve.     (Gerrish) 167 

105.  Diagram  of   a  cross-section  of  an  artery,  showing  the   composition 

of  its  tunics.     (Gerrish)        ........  169 

106.  Fine  capillaries  from  the  mesentery.     (Collins)  .         .         .         .170 

107.  Transverse  section  through  a  small  artery  and  vein,  showing  the  rela- 

tive difference  in  the  thickness  of  their  walls.     (Klein  and  Noble 

Smith) 171 

108.  Diagram  showing  valves  of  veins.       (Sharpey) 172 

110.  Valves  of  the  lymphatics      .         .         .         .         .         .         .         ,         .174 

111.  Lacteals  and  lymphatics,  during  digestion.     (Dalton)          .         .         .  175 

112.  A  lymph  node  with  its  afferent  and  efferent  vessels.     (Gerrish)          .  176 
116.    Diagram  showing   the  branchings,  anastomoses,  and   confluence  of 

arteries.     (Gerrish)       .         .         . 184 

138.  Diagram  of  circulation  before  birth.     (Cooke) 225 

139.  Diagram  of  the  essentials  of  a  respiratory  system.     (Gerrish)    .         .  232 

140.  Sagittal  section  of  the  face  and  neck,  showing  the  first  portions  of 

the  respiratory  and  alimentary  tracts.     (Gerrish)         .        .         •  233 

141.  Larynx.     (Gerrish) •         .         .         .         .  235 

142.  The  larynx  as  seen  by  means  of  the  laryngoscope  in  different  con- 

ditions of  the  glottis 236 

143.  Front  view  of  cartilages  of  larynx 237 

144.  Bronchi  and  bronchioles.     (Gerrish)  .......  239 

146.  Stethograph  tracing  of  Cheyne-Stokes  respirations  in  a  man.     (Hal- 

liburton)          248 

147.  The  soft  palate  and  tonsillar  regions.     (Gerrish)         ....  256 

148.  The  salivary  glands 257 

149.  Section  of  human  molar  tooth.     (Dalton)  ......  258 

150.  Regions  of  the  abdomen.     (Gerrish)   .......  262 

151.  The  stomach  and  intestines,  front  view,  the  great  omentum  having 

been  removed,  and  the  liver  turned  up  and  to  the  right.    (Gerrish)  2^4 
162.    Portion  of  small  intestine  laid  open  to  show  valvulae  conniventes. 

(Collins) 267 


xiv  LIST  OF  ILLUSTRATIONS 

FIO.  PAOB 

153.  An  intestinal  villus 207 

154.  Portion  of  the  mucous  membrane,  from  the  ileum.     (Dalton)    .         .  208 

155.  Mucosa  of  small  intestine  in  ideal  vertical  cross-section.     (Gerrish)  .  208 

156.  Aggregated  lymph  nodule  (Peyer's  patch).     (Gerrish)       .         .         .  209 

167.  Cavity  of  the  csecum,  its  front  wall  having  been  cut  away.    (Gerrish)  270 

168.  Ducts  of  the  pancreas.     (Gerrish) 272 

169.  The  liver.     (Gerrish) 274 

160.  The  liver.     (Gerrish) 274 

161.  Diagrammatic  representation  of  two  hepatic  lobules  ....  275 

162.  Lobule  of  rabbit's  liver,  vessels  and  bile  ducts  injected        .         .         .  270 
166.    Vertical  section  of  the  kidney.     (Collins) 326 

168.  Plan  of  the  blood-vessels  connected  with  the  tubules  ....  329 

169.  Diagram  showing  method  of  entrance  of  the  ureter  into  the  bladder. 

(Gerrish) 331 

170.  Vertical  section  through  the  skin  of  the  palmar  side  of  the  finger, 

showing  two  jjapillae  (one  of  which  contains  a  tactile  corpuscle) 

and  the  deeper  layer  of  the  epidermis.     (Schafer)        .        .        .  345 

171.  Thumb-nail.     (Gerrish) 347 

172.  Piece  of  human  hair 347 

173.  Vertical  section  of  the  skin,  showing  sebaceous  glands,  sweat-glands, 

hair,  and  follicle,  also  arrector  muscle.     (Gerrish)       .        .        .  349 

174.  Coiled  end  of  a  sweat-gland 350 

175.  A  neurone.     (Gerrish) 365 

176.  Sensory  nerve  terminations  in  stratified  pavement  epithelium.  (Kirkes)  369 

177.  Pacini's  corpuscle.     (Collins) 370 

178.  Diagram  illustrating  the  general  arrangement  of  the  cerebro-spinal 

system 374 

179.  Transverse  section  of  the  sciatic  nerve  of  cat  about  x  100  .        .         .  375 

180.  Transverse  section  of  the  spinal  cord  at  the  middle  of  the  thoracic 

region.     (Gerrish) 379 

181.  Diagram  of  nerve-roots  emerging  from  spinal  cord.     (Collins)  .        .  381 

182.  Degeneration  of  spinal  nerves  and  nerve-roots  after  section        ,         .  382 

185.  External  view  of  outer  side  of  right  cerebral  hemisphere,  showing 

Rolando,  Sylvian,  and  pariuto-occipital  fissures,  together  with 

principal  convolutions.     (Collins) 389 

186.  Mesial  view  of  left  cerebral  hemisphere,  showing  TJolandic  and  pa.- 

rieto-occipital  fissures,  together  with  the  principal  convolutions. 

(Collins) 390 

188.  Localization  of  function  in  the  cerebral  cortex.     (Woolsey)       .        .  393 

189.  Reflex  arc.     (Collins) 398 

190.  Diagram  of  nervous  system 400 

191.  The  upper  surface  of  the  tongue.     (Sappey) 412 

192.  Vertical  longitudinal  section  of  nasal  cavity 414 

193.  Semi-diagrammatic  section  through  the  right  ear         ....  415 

194.  Ossicles  of  the  tympanum,  x  4.     (Flint) 417 

195.  The  left  bony  labyrinth  of  a  new-born  child,  forward  and  outward 

view.     (Flint) 418 

1P6.    Diagram  showing  relative  position  of  the  planes  in  which  the  semi- 
circular canals  lie  .........         .  420 

197.  The  lacrimal  apparatus 422 


LIST  OF  ILLUSTRATIONS  xv 

FIG.  PAGE 

198.  Diagrammatic  section  of  tlie  eye.     (Flint)  , 424 

199.  Segment  of  tlie  iris,  ciliary  body,  and  clioroid.     (Gerrish)           .         .  426 

200.  Choroid  membrane  and  iris  exposed  by  the  removal  of  the  sclera  and 

cornea.     (Collins) 427 

201.  Diagrammatic  section  of  the  human  retina.     (M.  Schultze)        .         .  428 

202.  The  posterior  half  of  the  retina  of  the  left  eye  viewed  from  before. 

(Collins) 429 

203.  Diagram  of  optic  chiasm 430 

204.  Diagram  illustrating  rays  of  light  converging  in  (A)  a  normal  eye, 

(B)  a  myopic  eye,  and  (C)  a  hypermetropic  eye          .         .         .  432 

205.  Uterus,  Fallopian  tubes,  and  ovaries  —  posterior  view.     (Sappey)      .  443 

206.  Internal  organs  of  generation.     (Cooke)      ......  446 

207.  Sagittal  section  of  the  vagina  and  neighboring  parts.     (Gerrish)         .  449 

208.  Vulva  of  a  virgin.     (Gerrish) 450 

209.  Right  breast  in  sagittal  section,   inner  surface  of  outer  segment. 

(Gerrish) 454 

210.  Male  sexual  apparatus.     ( Hall) 457 


LIST    OF   COLORED   ILLUSTRATIONS 

no.  PAGE 

20.    Diagram  of  the  structure  of  osseous  tissue.     (Gerrish)        ...  45 

99.    Tha pulmonary  artery  and  aorta.     (Gerrish) 163 

101.   Left  auricle  and  ventricle,  the  hind  wall  of  each  having  been  re- 
moved.    (Gerrish) 165 

103.   Valves  of  the  heart  and  great  arteries,  viewed  from  above,  the  auricles 

having  been  removed.     (Gerrish) 166 

109.    The  regions  whose  lymph  flows  into  the  right  lymphatic  duct  are  sug- 
gested by  the  red  area ;  those  which  are  tributary  to  the  thoracic 

duct  by  the  blue  area.     (Gerrish) 173 

113.  The  lymph  nodes  and  vessels  of  the  upper  limb.     (Gerrish)        .         .  177 

114.  The  lymph  nodes  and  vessels  of  the  lower  limb.     (Gerrish)        .         .  178 

115.  The  lymph  nodes  of  the  neck  and  upper  part  of  the  thorax.    (Gerrish)  179 

117.  The  principal  arteries  of  the  body.     (Morrow) 186 

118.  Pulmonary  veins,  seen  in  a  dorsal   view  of   the   heart  and   lungs. 

(Gerrish) 187 

119.  Thoracic  aorta.     (Gerrish) 188 

120.  Abdominal  aorta.     (Gerrish) 189 

121.  Subclavian  and  axillary  arteries.     (Gerrish) 191 

122.  Deep  anterior  view  of  the  arteries  of  the  arm,  forearm,  and  hand       .  192 

123.  Superior  mesenteric  artery.     (Gerrish) 194 

124.  Inferior  mesenteric  artery.     (Gerrish) 195 

125.  Femoral  artery.     (Gerrish) 197 

126.  Arteries  in  the  dorsal  part  of  the  leg.     (Gerrish)        ....  198 

127.  Anterior  tibial  artery.     (Gerrish) 198 

128.  Arteries  of  the  dorsum  of  the  foot.     (Gerrish) 200 

129.  Superficial  veins  of  front  of  forearm  and  lower  part  of  arm.    (Gerrish)  202 

130.  Superficial  veins  of  front  of  arm  and  shoulder.     (Gerrish)           .         .  203 

131.  Veins  of  the  neck  and  upper  part  of  thorax.     Front  view.     (Gerrish)  204 

132.  Superficial  veins  of  the  front  of  the  leg  and  foot.   '(Gerrish)       .         .  206 

133.  Superficial  veins  of  the  front  of  the  right  thigh.     (Gerrish)         .         .  206 

134.  Superficial  veins  of  the  dorsum  of  the  leg.     (Gerrish)          .        .         .  207 

135.  Azygos  and  intercostal  veins.     (Gerrish) 208 

136.  Portal  system  of  veins.     (Gerrish)       .......  209 

137.  Diagram  of  the  circulation.     (Halliburton) 215 

145.   Diagram  of  a  lobule  of  the  lung.     (GeiTish) 241 

163.  The  thyroid  body  and  the  related  blood-vessels.     (Gerrish)        .         .  314 

164.  The  thymus,  the  sternal  and  costal  cartilages  having  been  removed. 

(Gerrish) 315 

165.  The  spleen,  showing  the  gastric  and  renal  surfaces  and  the  blood- 

vessels.    (Gerrish)        .........  318 

167.    Diagi-am  of  the  structure  of  a  lobe  of  the  kidney.     (Gerrish)      .         .  328 

183.  Under  surface  of  the  brain,  showing  the  superficial  origins  of  the 

cranial  nerves.     (Gerrish) 387 

184.  Falx  cerebri  and  tentorium,  left  lateral  view.     (Gerrish)    .         .        .  388 
187.   The  lobes  of  the  convex  surface  of  the  hemisphere,  left  side.    (Gerrish)  391 

xvii 


ATiATOMY  AND  PHYSIOLOGY 
FOR  NURSES 


CHAPTER  I 

EXPLANATIONS    AND    DEFINITIONS    OF    SOME    CHEMICAL    AND 
PHYSICAL   TERMS 

An  intelligent  discussion  of  the  various  functions  of  the  human 
body  cannot  be  given  without  some  elementary  considerations  in 
the  field  of  chemistry  and  its  intimately  related  science  of  physics. 
Probably  the  briefest  method  for  presenting  the  essential  points 
is  in  the  way  of  definitions  with  accompanying  illustrations,  and 
explanations  where  necessary. 

THE   PHYSICAL  SCIENCES 

1.  Physics  deals  with  mechanics,  heat,  light,  sound,  and  elec- 
tricity, and  their  relations  to  matter. 

2.  Chemistry  deals  with  change  in  the  composition  of  matter, 
the  energy  change  involved  therein,  and  the  principles  controlling 
chemical  change. 

MA^ITER 

1 .  Defined.  —  Matter  is  usually  defined  as  anything  that  oc- 
cupies space,  as  wood,  air,  water. 

2,  Forms  in  which  matter  exists. 

Elements.  —  An  element  is  a  substance  which  cannot  be  sepa- 
rated into  more  simple  substances  by  any  mea'ns  known  to  science 
at  present.  Elements  are  supposed  to  be  made  up  of  atoms  which 
are  alike  for  the  same  element  and  cannot  be  divided. 

There  are  about  eighty  of  these  elements,  less  than  half  of 
which  are  well  known.  Some  of  the  most  common  are  carbon, 
iron,  sulphur,  mercury,  and  oxygen. 

Compounds.  —  A  compound  is  a  substance  which  can  be  sepa- 
rated into  simpler  substances.  Compounds  are  supposed  to  be 
made  up  of  molecules  which  are  composed  of  .groups  of  atoms. 
Molecules  are  alike  for  the  same  compound  and  can  be  divided, 
giving  elements  or  simpler  compounds.  For  example,  water  is 
composed  of  hydrogen  and  oxygen,  each  molecule  having  in  it 

3 


4  ANATOMY   FOR   NURSES  [Chap.  I 

two  hydrogen  atoms  and  one  oxygen  atom  (II2O),  when  sepa- 
rated, water  gives  the  two  elements  hydrogen  and  oxygen.  Again, 
sugar  is  composed  of  hydrogen,  carbon,  and  oxygen,  each  mole- 
cule having  in  it  twelve  atoms  of  carbon,  twenty-two  atoms  of 
hydrogen,  and  eleven  atoms  of  oxygen  (C12H22O11),  when  sepa- 
rated it  gives  several  compounds  with  simpler  molecules,  as  car- 
bon dioxide  (CO2),  water  (H2O),  methane  (CIi4),  etc. 

Mixtures.  —  A  mixture  can  be  made  up  of  either  or  both  ele- 
ments and  compounds.  These  can  often  be  separated  by  simple 
physical  means,  as  filtration  or  evaporation.  ]\Iilk  is  a  mixture  of 
several  compounds,  —  water,  cream,  proteins,  sugar,  and  salts. 
The  cream  can  be  separated  by  allowing  the  milk  to  stand,  when 
it  will  rise  to  the  top,  and  can  be  skimmed  off.  Salt  solution  is 
a  mixture  of  the  compounds,  salt  and  water.  They  can  be  sepa- 
rated by  evaporating  the  water.  Air  is  a  mixture  of  compounds 
and  elements,  carbon  dioxide  (compound),  nitrogen  and  oxygen 
(elements).     They  cannot  be  separated  bj'  any  simple  means. 

3.   Matter  undergoes  changes. 

Physical  change.  —  When  matter  has  been  subjected  to  a 
change  which  does  not  affect  the  composition  of  the  matter,  the 
change  is  said  to  be  a  physical  one  only.  The  following  are 
given  by  way  of  illustration  :  — 

Water  can  solidify  (freeze)  or  it  can  vaporize ;  whether  it  exists 
in  the  state  of  a  solid,  a  liquid,  or  a  gas,  depends  upon  the  tempera- 
ture, but  the  composition  in  all  these  states  is  identical.  Sugar 
melts,  but  the  solid  sugar  and  the  liquid  sugar  are  exactly  the  same 
in  composition ;  the  change  is  only  one  in  physical  state. 

Other  physical  changes  besides  change  in  physical  state  are, 
change  in  size,  'position,  magnetic  or  electric  condition,  and  change 
in  temperature. 

Chemical  change.  —  V^Tien  matter  undergoes  a  change  in  com- 
position, it  is  said  to  have  undergone  a  chemical  change.  The 
following  are  illustrations :  when  an  electric  current  is  passed 
through  water,  the  water  is  separated  into  two  distinct  substances, 
hydrogen  and  oxygen.  In  this  case  we  start  with  a  single  com- 
pound (water)  of  definite  composition,  and  as  a  result  of  the 
change,  obtain  two  different  substances  (oxygen  and  hydrogen). 
Again,  in  a  bar  of  iron  there  is  nothing  but  the  element  iron, 
but  if  it  is  left  exposed  to  the  air,  it  is  converted  into  a  red 


Chap.  I]     EXPLANATIONS  AND   DEFINITIONS  5 

solid  which  has  iron  and  oxygen  in  it,  the  iron  having  combined 
with  some  of  the  oxygen  from  the  air.  The  iron  and  the  iron  rust 
are  evidently  different  in  composition. 


ELEMENTS  FOUND  IN  THE  BODY 


The  elements  found  in  the  body  are : 


Carbon, 

13.5 

(C) 

Hydrogen, 

9.1 

(H) 

Nitrogen, 

2.5 

(N) 

Oxygen, 

72. 

(0)j 

Sulphur, 

(S) 

Phosphorus, 

(P) 

Fluorine, 

(F) 

Chlorine 

(CI) 

Iodine, 

(I) 

Silicon, 

(Si) 

Sodium, 

(Na) 

Potassium, 

(K) 

Calcium, 

(Ca) 

Magnesium, 

(Mg) 

Lithium, 

(Li) 

Iron, 

(Fe) 

Manganese, 

(Mn) 

Copper, 

(Cu) 

Lead, 

(Pb) 

form  97  per  cent 
of  total 
weight  of  body. 


These  elements  are  not,  of  course,  found  uncombined  in  the 
body,  but  rather  combined,  usually  in  the  form  of  rather  complex 
compounds.  Protoplasm,  for  instance,  is  a  compound  of  carbon, 
hydrogen,  nitrogen,  oxygen,  and  phosphorus. 

ORGANIC  AND  INORGANIC  COMPOUNDS 

The  distinction  between  organic  and  inorganic  compounds 
dates  back  to  an  early  period,  when  there  was  a  belief  that  cer- 
tain compounds  of  carbon  found  in  living  organisms  could  only 
be  built  up  through  the  agency  of  a  vital  force  possessed  by  the 
organism,  which  prevented  their  being  synthesized  in  the  chemical 
laboratory.  In  distinguishing  such  they  were  spoken  of  as  organic 
compounds.     However,  when  urea,  one  of  these  substances,  was 


6  ANATOMY  FOR  NURSES  [Chap.  I 

prepared  in  the  laboratory,  this  theory  was  abandoned,  but  the 
distinctive  terms  organic  and  inorganic  persisted.  Under  the 
present  classification  organic  compounds  are  compounds  that  con- 
tain carbon. 

Because  of  the  fact  that  there  are  numerous  carbon  compounds  and 
also  because  many  of  these  can  be  grouped  into  classes  with  weU-defined 
characteristics,  the  study  of  the  carbon  compounds  has  become  a  separate 
phase  of  the  general  study  of  chemistry  and  is  called  organic  chemistry. 

SOME  CHEMICAL  TERMS 

Atom.  —  An  atom  is  the  smallest  part  into  which  an  element 
can  be  divided.  Atoms  are  alike  for  the  same  element,  but 
different  for  different  elements. 

Molecule.  — ^  A  molecule  is  a  group  of  atoms  in  chemical  com- 
bination. Compounds  are  made  up  of  multitudes  of  molecules, 
all  of  which  are  alike  for  the  same  compound. 

Chemical  formula. — A  chemical  formula  is  a  simple  means 
for  representing  the  composition  of  the  molecule.  Symbols  are 
made  use  of  to  represent  the  elements  and  small  subscript  figures 
to  represent  the  number  of  atoms  of  the  respective  elements. 
For  example,  the  formula  for  the  sulphuric  acid  molecule  (H2SO4) 
shows  it  to  be  made  up  of  two  atoms  of  hydrogen,  one  atom  of 
sulphur,  and  four  atoms  of  oxygen ;  the  formula  for  the  sodium 
chloride  molecule  (XaCl)  shows  it  to  be  made  up  of  one  atom  of 
sodium  and  one  of  chlorine. 

Chemical  equation.  —  A  chemical  equation  is  a  simple  means 
for  representing  the  matter  change  that  takes  place  in  a  chemical 
action.  When  carbon  burns  it  combines  with  oxygen  to  form 
carbon  dioxide.     The  equation  that  expresses  this, 

C  +  O2  ->  CO2, 

tells  that  during  the  process  of  combination,  one  atom  of  carbon 
combines  with  one  molecule  of  oxygen  (composed  of  two  atoms)  to 
give  one  molecule  of  carbon  dioxide.  In  the  action  of  sodium 
hydroxide  with  hydrochloric  acid,  water  and  sodium  chloride  are 
formed.     The  equation  to  represent  this, 

NaOH  +  HCl  ->  H2O  +  NaCl, 

shows  that  one  molecule  of  sodium  hydroxide  reacts  with  one  mole- 


Chap.  I]     EXPLANATIONS   AND   DEFINITIONS  7 

cule  of  hydrochloric  acid  to  give  one  molecule  of  water  and  one 
molecule  of  sodium  chloride. 

Oxide. — An  oxide  is  a  compound  in  which  another  element 
is  in  combination  with  oxygen,  as  water  (H2O),  carbon  dioxide 
(CO2),  sulphur  dioxide  (SO2),  and  iron  oxide  (Fe203). 

Acid  oxide. — -An  acid  oxide  (or  acid  anhydride)  is  an  oxide 
of  a  non-metal  which  in  combination  with  water  will  form  an 
acid,  as  carbon  dioxide  and  sulphur  dioxide,  as  shown  in  the 
following :  — 

CO2  +  H2O  ->  H2CO3  (carbonic  acid), 
SO3  +  H2O  ->  H2SO4  (sulphuric  acid). 

Basic  oxide.  —  A  basic  oxide  (or  basic  anhydride)  is  an  oxide 
of  a  metal  which  in  combination  with  water  will  give  a  base, 
as  calcium  oxide  (CaO)  and  sodium  oxide  (Na20),  shown  in  the 
following :  —  . 

CaO    +  H2O  -^  Ca(0H)2  (calcium  hydroxide), 
NaoO  +  H2O  ->  2  NaOH  (sodium  hydroxide). 

Acid. — An  acid  is  a  substance  which  contains  hydrogen  and 
an  acid  radical.  The  acid  radical  must  contain  a  non-metal  and 
may  contain  ox;y'gen.  Examples  are  hydrochloric  acid  (HCl), 
sulphuric  acid  (H2SO4),  carbonic  acid  (H2CO3),  hydrobromic  acid 
(HBr),  nitric  acid  (HNO3). 

Base.  — A  base  is  a  substance  which  contains  a  metal  and  the 
hydroxyl  (OH)  radical.  Examples  are  sodium  hydroxide  (NaOH) 
and  calcium  hydroxide  (Ca(0H)2).  One  exception  to  this  is 
ammonium  hydroxide  (NH4OH),  which  contains  the  ammonium 
radical  (NH4)  instead  of  a  metal. 

The  alkalies  are  the  bases  of  sodium,  potassium,  and  ammonium ; 
they  give  very  strong  basic  action. 

Both  acids  and  bases  give  distinctive  characteristic  actions. 

Salt.  —  A  salt  is  a  substance  containing  the  metal  from  a  base 
and  the  acid  radical  from  an  acid.  Salts  may  be  obtained  by  the 
neutralization  of  an  acid  by  a  base,  the  characteristic  hydrogen  of 
the  acid  combining  with  the  characteristic  hydroxyl  of  the  base 
to  form  water,  leaving  the  salt  as  shown  in  the  following :  — 

Base  +  Acid      —>  Water  +  Salt 

NaOH      +HC1     ^H20     +  NaCl     (sodium  chloride), 

Ca(0H)2  +  H2SO4  -^  2  H2O  +  CaS04  (calcium  sulphate). 


8  ANATOMY  FOR  NURSES  [Chap.  1 

SOME  GENERAL  CHEMICAL  ACTIONS 

Oxidation.  —  Oxidation  is  the  process  in  which  the  element 
oxj^gen  combines  chemically  with  another  substance,  heat  being 
evolved  in  the  process.  The  heat  evolved  may  not  be  perceptible 
unless  the  oxidation  takes  place  rapidly,  as  in  the  burning  of  gas, 
wood,  coal,  etc.  If  the  substance  combines  slowly  with  oxj^'gen, 
heat  may  be  imperceptible ;  for  example,  iron  allowed  to  lie  in 
moist  air  is  covered  with  rust  due  to  the  union  of  the  iron  and 
oxygen.  Also  in  our  bodies  some  of  the  carbon  from  the  cells 
unites  with  oxj'gen,  and  thus  the  temperature  of  the  body  is  kept 
up.  It  is  for  this  reason  that  ox;>'gen  must  be  taken  into  the 
body,  which  is  accomplished  by  the  act  of  breathing. 

Neutralization.  —  Neutralization  is  the  process  that  takes  place 
in  the  action  of  an  acid  with  a  base.  Water  and  salt  are  the 
products  of  the  reaction.      (See  Salt.) 

Hydrolysis.  — Hydrolysis  can  be  defined  as  the  chemical  change 
that  takes  place  when  a  compound  in  its  action  with  water  splits 
into  two  other  compounds,  fixing  the  elements  of  water  in  the 
process.  The  action  of  water  with  some  salts,  also  the  formation 
of  glucose  and  fructose  from  cane  sugar,  may  be  given  as  examples, 
as  represented  in  the  following  reaction  equations :  — 

(Sodium  carbonate)  (Sodium  hydroxide)        (Carbonic  acid) 

NasCOa     +2H20^    2  NaOH        +     H2CO3, 

(Cane  sugar)  (Fructose)  (Glucose) 

C12H22O11  +  H2O     ->    CeHiiOe  +     CeHioOe. 

Hydration.  —  Hydration  is  the  process  by  which  water  enters 
into  direct  combination  with  another  compound  to  form  a  single 
compound  which  is  called  a  hydrate.  As  examples  might  be 
given,  sulphuric  acid  as  a  hydrate  of  sulphur  trioxide,  calcium 
hydroxide  as  a  hydrate  of  calcium  oxide,  and  crystalline  cop- 
per sulphate  as  a  hydrate  of  anhydrous  copper  sulphate.  The 
formation  of  these  hydrates  in  the  process  of  hydration  is 
represented  in  the  following :  — 


Anhydrous 

substances 

Hydrates 

SO3           + 

H2O    :^H2S04 

CaO       + 

H2O     :^Ca(0H)2 

CUSO4    + 

5  H2O  :^  CUSO4 . 5  H2O. 

Chap.  I]     EXPLANATIONS   AND   DEFINITIONS  9 

The  reverse  process  by  which  a  compound  is  split  up  into  water 
and  an  anhydrous  compound  is  called  dehydration.  This  process 
is  represented  in  the  equations  by  the  reverse  arrows. 

ENERGY 

Energy  is  ordinarily  defined  as  the  power  of  doing  work.  As 
examples  of  various  types  of  energy  might  be  mentioned :  mechani- 
cal energy,  heat  energy,  electrical  energy,  and  chemical  energy. 
These  can  be  transformed  from  one  form  to  another.  To  illustrate : 
(1)  electrical  energy  can  be  converted  into  energy  of  motion,  as 
evidenced  in  the  motor ;  (2)  electrical  energy  can  be  converted  into 
heat  energy,  as  in  the  electric  stove ;  (3)  mechanical  energy  of 
motion  can  be  converted  into  electrical  energy,  as  in  the  dynamo ; 
also,  (4)  chemical  energy  can  be  transformed  into  heat  energy, 
as  is  true  in  the  burning  of  wood. 

SOME  PHYSICAL  TERMS 

Specific  gravity.  —  By  specific  gravity  is  meant  the  comparison 
between  the  weight  of  a  substance  and  the  weight  of  an  equal 
volume  of  some  other  substance  taken  as  a  standard.  The 
standards  usually  referred  to  are  air  for  gases,  and  water  for  liquids 
and  solids.  For  instance,  the  specific  gravity  (sp.  gr.)  of  mercury 
is  13.6,  meaning  that  mercury  is  13.6  times  as  heavy  as  an  equal 
volume,  of  water.  Again,  the  specific  gravity  of  carbon  dioxide 
(air  standard)  is  1.5,  meaning  that  it  is  1.5  times  as  heavy  as  an 
equal  volume  of  air. 

The  specific  gravity  of  solutions,  as  a  salt  solution,  will  neces- 
sarily vary  with  the  concentration. 

Diflfusion.  —  This  term  in  its  ordinary  use  has  to  do  with  the 
tendency  of  two  liquids  or  two  gases  of  different  densities  to  mix 
uniformly.  Diffusion  can  take  place  either  when  the  substances 
are  simply  superimposed,  or  when  they  are  separated  by  a  per- 
meable membrane.  The  following  illustrations  may  help  to  make 
this  clear. 

1.  When  the  gases  or  liquids  are  not  separated  by  a  membrane. 

(a)  If  a  bottle  of  hydrogen  is  inverted  over  a  bottle  of  chlorine 
gas,  the  lighter  hydrogen  molecules  will  move  down  among  the 
chlorine  molecules,  while  the  heavier  chlorine  molecules  will  move 


10  ANATOMY  FOR  NURSES  [Chap.  I 

up  to  mix  with  the  hydrogen  molecules,  so  that  the  two  will  eventu- 
ally be  mixed  uniformly. 

(6)  If  a  layer  of  water  is  placed  carefully  over  a  layer  of  sulphuric 
acid,  in  such  a  way  that  the  two  do  not  mix,  two  distinct  layers 
will  be  formed  with  the  heavier  sulphuric  acid  at  the  bottom. 
The  acid  molecules  will  begin  to  move  up  and  mix  with  the  water 
molecules,  while  the  water  molecules  will  move  down  to  mix  with 
the  sulphuric  acid  molecules.  The  action  is  much  slower  than 
with  the  gases. 

2.  When  the  gases  or  liquids  are  separated  by  certain  membranes. 

(c)  In  the  illustration  given  in  (a)  if  a  membrane,  permeable 
to  gases,  be  stretched  over  the  mouth  of  the  bottle,  the  gases 
wull  mix  evenly  through  it.  Also,  if  a  membranous  sac  of  carbon 
dioxide  is  placed  in  a  vessel  containing  oxygen,  the  two  gases  will 
diffuse  through  the  membrane,  until  the  mixture  of  gases  inside 
and  outside  is  uniform. 

(d)  When  a  bladder  of  alcohol  is  immersed  in  water,  the  two 
liquids  will  diffuse  through  the  membrane;  the  water  diffusing 
more  rapidly  than  the  alcohol,  the  bladder  will  become  distended. 

This  subject  of  diffusion  is  an  important  one,  as  it  has  a  great 
deal  to  do  with  life  and  with  physiological  processes.  Because 
of  diffusion  the  heavier  carbon  dioxide  in  the  atmosphere  is  pre- 
vented from  settling  to  the  bottom  of  the  atmosphere,  thereby 
forming  a  layer  of  the  same  next  to  the  earth,  a  condition  which 
would  seem  to  make  life  impossible.  Diffusion  of  gases  through 
membranes  makes  possible  the  exchange  of  carbon  dioxide  and  oxy- 
gen through  the  walls  of  the  lungs.     (See  page  246.) 

The  explanation  of  the  process  is  found  in  the  suppositions  of 
the  Jcinetic  theory  that :  — 

1.  There  are  spaces  between  the  molecules  making  up  all  bodies. 

2.  Molecules  are  in  rapid  motion  in  straight  lines,  the  motion  of 
gas  molecules  being  much  more  rapid  and  unrestrained  than  in  the 
case  of  liquid  molecules. 

Two  forms  of  diffusion  are  spoken  of  distinctively  as  osmosis 
and  dialysis. 

Osmosis.  —  If  a  solution  is  separated  from  the  clear  solvent 
by  a  membrane,  which  is  permeable  to  the  liquid  but  not  to  the 
substance  in  solution,  the  liquid  will  pass  through  the  membrane 
and  the  volume  on  the  side  of  the  solution  will  be  increased.     Also, 


Chap.  I]     EXPLANATIONS  AND   DEFINITIONS  11 

if  two  solutions  of  different  concentrations  are  used  with  the 
separating  membrane,  the  volume  on  the  side  of  the  solution  of 
greater  concentration  will  be  increased. 

For  example,  if  a  carrot  with  the  inside  hollowed  out  is  filled 
with  a  sugar  solution,  a  long  glass  tube  secured  in  the  opening 
and  the  carrot  then  placed  in  a  vessel  of  water  or  a  solution  of  less 
concentration,  the  volume  of  the  solution  inside  the  carrot  will 
increase  as  indicated  by  the  rise  in  the  glass  tube.  If  conditions 
are  reversed  and  the  less  concentrated  solution  is  placed  in 
the  membrane,  the  increase  in  volume  will  be  in  the  outer  vessel. 
This  phenomenon  of  osmosis,  therefore,  accounts  for  the  swelling 
of  dried  fruits  in  water  and  the  rising  of  water  into  the  stems  and 
leaves  of  plants.     (See  page  154.) 

No  completely  satisfactory  explanation  is  given  for  this 
process  of  osmosis.  A  most  acceptable  one,  however,  is  found 
in  the  kinetic  theory.  According  to  this  theory,  the  molecules 
of  liquid  and  solute  are  both  bombarding  the  membrane  on  each 
side.  The  molecules  of  the  liquid  can  pass  through,  but  the  mole- 
cules of  the  solute  cannot,  the  membrane,  therefore,  being  called 
semi-permeable.  The  number  of  liquid  molecules  bombarding  the 
membrane,  per  unit  area,  on  the  side  of  the  clear  solvent,  or  less 
concentrated  solution,  will  be  greater  than  the  number  of  liquid 
molecules  bombarding  the  membrane  on  the  side  of  the  more  con- 
centrated solution,  hence,  more  liquid  molecules  will  pass  from 
the  less  concentrated  to  the  more  concentrated  solution  and  the 
volume  of  the  latter  will  be  thereby  increased.  This  increase  will 
continue  until  the  pressure  in  both  directions  is  the  same. 

Osmotic  pressure.  —  This  is  a  term  that  is  used  indefinitely,  and 
to  express  a  fact  rather  than  an  understood  force.  A  possible 
explanation  is  as  follows :  the  molecules  in  their  vibratory  motion 
in  the  process  of  diffusion  exert  a  certain  force  which  is  evident 
as  a  pressure  when  striking  against  anything  in  their  path.  This 
force  or  pressure  is  spoken  of  as  osmotic  pressure.  When  there- 
fore a  solution  is  held  confined  the  vibratory  force  or  osmotic 
pressure  of  the  molecules  within  the  mass  produces  an  evident 
pressure  against  the  sides  of  the  containing  vessel.  It  is  to  this 
pressure  that  the  process  of  osmosis  is  due,  for  if  the  side  of  a 
vessel  is  a  permeable  membrane,  the  molecules  in  pressing  against 
it  will  pass  through. 


12  ANATOMY  FOR  NURSES  [Chap.  1 

Dialysis.  —  In  this  process  a  permeable  membrane  is  selected 
which  will  admit  of  the  passage  of  a  substance  in  solution.  For 
example,  if  a  tumbler  is  completely  divided  vertically  into  two 
compartments  by  a  moist  piece  of  membrane  and  a  water  solution 
of  common  salt  is  placed  in  one  compartment  and  a  water  solution 
of  sugar  in  the  other,  it  will  be  found  after  a  time  that  some  of  the 
salt  has  passed  into  the  solution  of  sugar,  and  vice  versa  some  of 
the  sugar  into  the  salt  solution.  Such  an  interchange  is  said  to 
be  due  to  dialysis,  and  if  the  process  is  allowed  to  go  on  for  some 
hours,  the  same  proportion  of  salt  and  sugar  will  be  found  in  the 
solution  on  each  side  of  the  dividing  membrane.     (See  page  154.) 

Emulsion.  —  When  a  substance  scatters  evenly  throughout 
a  liquid  in  such  a  finely  divided  form  that  it  cannot  be  separated 
from  the  liquid  by  filtration,  but  has  a  tendency  to  separate  like 
matter  in  suspension,  the  system  is  spoken  of  as  an  emulsion. 
This  separation  may  take  place  in  a  brief  time,  or  it  may  require 
a  week,  or  month,  or  even  a  year.  Oil  shaken  thoroughly  in 
water  furnishes  an  example. 

UNIT  FOR  MEASURING  HEAT 

Inasmuch  as  heat  is  a  form  of  energj'',  it  is  not  as  simple  an  under- 
taking to  speak  of  it  in  comparative  terms  as  in  the  case  of  matter. 
It  is  easy  for  one  to  visualize  five  quarts  of  milk  as  five  times  a 
certain  volume  that  has  been  taken  as  a  standard  and  called  one 
quart.  So  it  is  also  with  weights  and  distances,  and  the  measure- 
ment of  weights,  distances,  and  volumes  is  a  necessary  part  of  our 
experience.  It  is  quite  as  urgent  that  there  should  be  a  basis  for 
the  comparison  of  energy  values  as  well  as  for  matter  values,  else 
the  coal  dealer  could  not  place  the  value  of  his  coal  on  a  basis  of 
its  heat-producing  qualities,  nor  could  the  dietitian  plan  the  meals 
on  a  basis  of  the  ultimate  energy-producing  qualities  to  the  individ- 
ual. We  are  only  conscious  of  energy  as  a  result  of  the  effect  it 
produces,  consequently,  if  it  is  to  be  measured,  it  must  be  on  this 
basis.  The  units  most  used  for  measuring  heat  are  the  small 
calorie  and  the  large  calorie. 

Small  calorie.  —  The  small  calorie  (cal.)  is  the  amount  of  heat 
that  is  necessary  to  raise  one  gram  of  water  through  one  degree 
centigrade. 

In  the  complete  combustion  of  12  grams  of  carbon,  94,300  cal. 


Chap.  I]     EXPLANATIONS   AND   DEFINITIONS  13 

are  liberated,  or  suflBcient  heat  energy  to  raise  943  grams  of  water 
through  100  degrees. 

When  25  grams  of  sugar  are  oxidized,  100  calories  of  heat  energy 
are  produced ;  therefore,  if  the  sugar  is  used  as  a  food,  the  energy 
produced  by  the  same  can  be  expected  to  be  proportionate  to  this 
estimate. 

Large  calorie. — ^The  large  calorie  (cal.)  is  the  amount  of 
heat  that  is  necessary  to  raise  1000  grams  of  water  through  one 
degree  centigrade.  This  shows  the  large  calorie  to  be  equal  to 
1000  small  calories.     (See  page  311.) 


CHAPTER  II 

DEFINITIONS.  —  CAVITIES    OF   THE   BODY 

DEFINITIONS 

Before  taking  up  the  subjects  of  anatomy  and  physiology  in 
detail,  it  is  well  first  of  all  to  consider  the  definitions  of  these 
terms  as  follows :  — 

Anatomy  refers  to  the  structure  of  the  body. 

Physiology  refers  to  the  functions  of  the  different  parts  of  the 
body,  in  a  state  of  health. 

Anatomy  teaches  us  what  organs  a  plant  or  animal  has,  and  how 
they  are  arranged  with  reference  to  one  another.  Physiology 
teaches  us  the  uses  to  which  these  organs  are  put.  Anatomy 
shows  what  an  organ  is ;  physiology  shows  what  an  organ  does. 
Anatomy  may  be,  and  usually  is,  studied  upon  the  dead  crea- 
ture ;    physiology  can  be  studied  only  upon  the  living  creature. 

Anatomy  is  sometimes  divided  into  the  following  branches :  — 

Osteology  is  the  anatomy  of  the  bones. 
Syndesmology  is  the  anatomy  of  the  joints. 
Myology  is  the  anatomy  of  the  muscles. 
Angiology  is  the  anatomy  of  the  vessels. 
Neurology  is  the  anatomj'^  of  the  nerves. 
Splanchnology  is  the  anatomy  of  tlic  internal  viscera. 
Adenology  is  the  anatomy  of  the  glands. 
Dermatology  is  the  anatomy  of  the  skin. 
Genesiology  is  the  anatomy  of  the  generative  organs. 

The  Anatomical  Position.  —  In  describing  the  body,  anatomists 
always  consider  it  as  being  in  the  erect  position,  with  the  face 
toward  the  observer,  the  arms  hanging  at  the  sides,  and  the  palms 
of  tlie  hands  turned  forward. 

Surfaces  of  the  Body.  —  When  the  body  is  in  the  anatomical 
position,  the  front,  or  surface  facing  the  observer,  is  named  the 
anterior  or  ventral  surface.  (See  Fig.  1.)  The  back,  or  surface 
directed  away  from  the  observer,  is  named  the  posterior  or  dorsal 
surface.     (See  Fig.  2.) 

14 


rfFTH  marr  on  Lrrn.E  toe-^ 

rOURTM  DIGIT  OH  FOOFTTH  TOE 

TMIRO  DIGIT  OR  THIRD  T0£ 
SECOND  DIGIT  OR  SECOND  1  ._ 

FIRST  DIGIT  OR  GREAT  T06 


mcrruB  ouintto^ 

"  DIGITUS  MINIMUM 
DIGITUS  OUARTU» 
^       DIGITUS  TERTIUS 
DIGITUS  6ECUNDUS 
IICITU8  PRIMUS,  HALIUX,  POlLTH  PCOIff 


lateral  J'nfTthT''/''''^,  °k  n  ^-^V  ^""^  Anatomical  Position.  On  the  right 
h£hL  rlrL  "^  r'  '^^u'""^  '°  ^°^"'^'  ^'^  the  left  in  Latin.  The  right  upper 
pTssib  e  when  itT/  "^  the  trunk  in  order  to  show  the  arm  more  luUy  than  is 
possiDie  when  it  hangs  perpendicularly.     (Gerrish.) 

15 


MALLEOLUS ExTERNua 


Fig.  2.  —  Back  View  of  a  Max.     On  the  left  lateral  half  the  names  of  the  parts 

are  given  in  English,  on  the  right  in  Latin.     (Gerrish.) 

16 


Chap.  II] 


DEFINITIONS 


17 


The  Median  Line.  —  This  refers  to  an  imaginary  line  drawn 
through  the  middle  of  the  body,  from  the  top  of  the  head  to  the 
middle  of  the  floor  between  the  feet,     The  parts  nearest  this  line 
are  described  as  medial,  the  parts  farthest 
from  this  line  are  described  as  lateral. 

Internal  and  External.  —  These  terms 
are  used  to  designate  within  and  without 
the  body  itself,  also  within  and  without 
the  body  cavities. 

Proximal  and  Distal.  —  Proximal  is  used 
to  describe  a  position  near  the  head  or 
source  of  any  part.  Distal  is  used  to  de- 
scribe a  position  distant,  or  farthest  away 
from  the  head  or  source  of  any  part. 

Periphery.  —  This  term  is  used  to  de- 
scribe the  circumference  of  a  circle,  hence 
in  anatomy  it  means  the  part  farthest  from 
the  centre. 

THE  HUMAN  BODY 

It  is  necessary  to  have  the  clearest  pos- 
sible conception  of  the  main  divisions  and       -c     o      t^ 

_    ^  _  hiG.  3.  —  Diagrammatic 

the  positions  of  the  different  parts  of  the  Longitudinal  Section  op 
11  1  1     11    .1         e  jt         ,1        THE  Trunk  AND  Head.  1,1, 

body,  and  we  shall  therefore  outline  the   the  dorsal  cavity;  a,  the 

structure  of  the  body  as  a  whole.     It  is   ^p^"^^  portion ;  b.  the  cra- 
nial enlargement ;   c,  c,  the 

readily  seen  that  the  human  body  is  sep-  bodies  of  the  vertebrce  form- 
arable  into  trunk,  head,  and  limbs;  the  Te dtLCd  ^tSu^ 
trunk  and  head  are  cavities,  and  contain   ties ;  2, 2,  the  ventral  cavity, 

,       .  ,  .  1       1  •!        1         subdivided     into     thoracic 

the  internal  organs,  or  viscera,^  while  the  cavity  (d),  abdominal  cavity 
limbs  are  solid,  contain  no  viscera,  and    ^');,^°^  '^f'''  ^f^^*-^  ({[= 

'  '  g,  the  nasal  cavity;    /(,  the 

are  merely  appendages  of  the  trunk.  mouth,  or  buccal   cavity. 

g~i      ..'  r   J.1-      -L     J  rni        .  i  i     The  alimentary  canal  (al)  is 

Cavities  of   the  body.  —  ihe  trunk  and    represented  running  through 

head  contain  two  main  cavities,  and  look-   the  whole  length  of  the  ven- 
tral cavity. 
ing  at  the  body  from  the  outside  we  should 

naturally  imagine  that  these  two  cavities  were  the  cavity  of  the 
head  and  the  cavity  of  the  trunk,  respectively.  If,  however,  we  di- 
vide the  trunk  and  head  lengthwise  into  two  halves,  by  cutting 

1  Viscera  is  the  plural  of  the  Latin  word  viscus,  which  means  an  organ  ;  hence 
viscera  are  organs  contained  within  the  body  cavities.     Example  :  heart,  stomach, 
etc.     Each  of  these  may  be  called  a  viscus. 
c 


18 


ANATOMY   FOR  NURSES 


[Chap.  II 


them  through  the  middle  line  from  before  backwards,  we  find  the 
trunk  and  head  are  divided  by  the  bones  of  the  spine  into  dorsal 
and  ventral  cavities,  and  not  into  upper  and  lower.     (See  Fig.  3.) 

1.  Dorsal  cavity. — The  dorsal  or  back  cavity  is  a  complete 
bony  cavity,  and  is  formed  by  the  bones  of  the  skull,  and  the 
vertebrae  (bones  of  the  spine).     It  may  be  subdivided  into:  — 

a.  The  cranial  cavity.  —  This  cavity  contains  the  brain. 
6.  The  spinal  canal.  —  This  canal  contains  the  spinal  cord,  which 
is  continuous  wMth  the  brain. 

2.  Ventral  cavity.  —  The  ventral  or  front  cavity  is  not  a  com- 
plete bony  cavity,  part  of  its  walls  being  formed  of  muscular  and 


Fig.  4.  —  Position  of  the  Thoracic  and  Abdominal  Organs  (Front  View). 

(Morrow.) 

other  tissue ;  it  is  much  larger  than  the  dorsal  cavity,  and  may 
be  subdivided  into :  — 


Chap.  II] 


CAVITIES  OF  THE   BODY 


19 


a.  Orbital  cavity.  —  The  orbital  cavity  contains  the  eye,  the  optic 
nerve,  the  muscles  of  the  eyeball,  and  the  lacrimal  apparatus. 

b.  Nasal  cavity.  —  The  nasal  cavity  is  filled  in  with  the  struc- 
tures forming  the  nose. 

c.  Buccal  cavity.  —  The  buccal  cavity  or  mouth  contains  the 
tongue,  teeth,  and  salivary  glands. 

d.  Thoracic  cavity.  —  The  thoracic  cavity,  or  chest,  contains 
the  trachea  or  windpipe,  the  lungs,  oesophagus  or  gullet,  heart,  and 
the  great  vessels  springing  from,  and  entering  into,  the  heart. 


Fig.  5.  —  Position  of  the  Thoracic  and"  Abdominal  Organs  (Rear  View). 

(Morrow.) 

Diaphragm.  —  The  diaphragm  is  a  dome-shaped  muscle,  and 
forms  a  transverse  partition  between  the  thoracic  and  adbominal 
cavities. 


20 


ANATOMY   FOR   NURSES 


[Chap.  II 


c.  Abdoiniiial  cui'ity.  —  The  ubdomiiuil  cavity  contuiii.s  the  stom- 
ach, Hver,  gall-bladder,  pancreas,  spleen,  kidneys,  small  and  large 
intestines,  etc. 

/.  Pelvic  cavity.  —  The  pelvic  cavity  is  that  portion  of  the  ab- 
domen lying  below  an  imaginary  line  drawn  across  the  prominent 
crests  of  the  hip  bones.  It  is  more  completely  bounded  by  bony 
walls  than  the  rest  of  the  abdominal  cavity.  It  contains  the  blad- 
der, rectum,  and  some  of  the  generative  organs. 

The  limbs,  or  extremities,  ui)per  and  lower,  are  in  pairs,  and 
bear  a  rough  resemblance  to  one  another,  the  shape  of  the  bones, 
and  the  disposition  of  the  muscles  in  the  thigh  and  arm,  leg  and 
forearm,  ankle  and  wrist,  foot  and  hand,  being  very  similar. 
There  is,  however,  a  marked  difference  between  the  mobility 
of  the  upper  and  the  lower  limbs.  The  shoulder  is  freely 
movable,  not  so  the  hip. 

SUMMARY 

IP-     I  "■  Cranial  cavity  —  Brain. 

I  h.   Spinal  canal  —  Spinal  cord. 
r  Eye. 
Optic  nerve. 
Muscles  of  tlic  eyeball. 
Lacrimal  apparatus. 
Structures  forming  the 
nose. 

I  Tongue. 
Teeth. 
Salivary  glands. 

,    ^,         .  f  Esophagus — Trachea. 

(I.  Thoracic  K       '      ^.,      , 

<  J.ungs  —  Heart. 

[  Iil(jod-vessels. 

The    Diaphragm    nuiscle    separates     the 

thoracic  and  al)doininal  cavities. 

Stomach  —  Spleen  — 

Pancreas. 

Liver — Gall-bladder. 

Kidneys  —  Large  and 

small  intestines. 

Bladder  —  Rectum. 

Some  of  the  generative 

I      organs. 


HUMAN 
BODY 


Ventral  Cavity 


(I.   Orbital  cavity 


b.   Nasal  cavity     | 


Abdominal 
cavity 


/.    Pelvic  cavity 


CHAPTER   III 

CELLS,  TISSUES,  ORGANS,  AND  SYSTEMS.  — EPITHELIAL  TISSUE: 
SIMPLE,   TRANSITIONAL,   STRATIFIED 

From  the  standpoint  of  the  chemist  the  body  is  composed  of 
elements.  (See  page  3.)  From  the  standpoint  of  the  anatomist 
the  body  is  composed  of  cells,  and  they  are  regarded  as  the  struc- 
tural units  out  of  which  either  directly  or  indirectly  it  is  built. 
If  the  substance  of  any  part  of  the  body,  i.e.  skin,  muscle,  or  blood, 
is  examined  with  the  imaided  eye,  it  appears  homogeneous,  but 
if  examined  with  the  microscope  it  is  found  to  be  composed  of 
an  innumerable  number  of  these  minute  cells.  ,  It  is  helpful  to  re- 
call that  low  down  in  the  scale  of  life  we  find  animals  so  simple 
that  they  are  described  as  consisting  of  just  one  cell.  As  we 
ascend  in  the  scale  of  life,  we  find  animals  that  consist  of  a  greater 
number  of  cells,  until  the  human  body  may  be  properly  described 
as  an  enormous  aggregate  of  cells. 

All  the  varied  activities  of  the  body  are  the  result  of  the  activity 
of  the  cells  which  compose  it,  and  it  is  very  desirable  that  we  early 
acquire  some  definite  conception  of  these  tiny  elementary  bodies. 

CELLS 

A  cell  ^  is  a  minute  portion  of  li\'ing  substance  or  protoplasm 
which  is  sometimes  enclosed  in  a  cell  membrane  or  cell  wall. 
Within  the  protoplasm  lies  a  body  of  definite  rounded  form,  called 
the  nucleus,  and  this  in  turn  often  contains  one  or  more  smaller 
bodies  or  nucleoli.  As  the  substance  of  the  entire  cell  is  proto- 
plasm, that  portion  which  surrounds  the  nucleus  is  given  the 
name  cytoplasm,  and  the  substance  of  the  nucleus  is  named 
karyoplasm. 

1  The  word  cell  is  from  the  Lutin  cella  —  a  cavity  —  and  was  first  used  by  bot- 
anists to  describe  plant  cells,  like  those  of  cork  and  elder  pith,  which  have  cavities 
in  their  substance.  It  is  now  known  that  most  animal  cells,  and  many  plant  cells, 
do  not  have  cavities,  so  that  the  name  is  not  especially  appropriate,  but  it  is  too 
firmly  fixed  in  our  language  to  be  abandoned. 

21 


22 


ANATOMY  FOR   NURSES 


[Chap.  Ill 


Cytoplasm.  —  The  cytoplasm  is  a  viscid  semi-fluid  substance, 
sometimes  homogeneous,  often  granular,  and  has  the  appear- 
ance of  a  meshwork.  In  this  meshwork  are  often  suspended 
various  passive  bodies,  such  as  food  granules,  pigment  bodies, 
drops  of  oil  or  water.  These  may  represent  reserve  food  matters, 
or  waste  matters,  and  are  collectively  designated  as  metaplasm. 

Nucleus.  —  The  structure  of  the  nucleus  is  similar  to  that  of 
the  cytoplasm,  hut  it  is  more  solid,  and  differs  in  chemical  com- 
position. It  is  bounded  by  a  membrane  which  separates  it  from 
the  surrounding  cytoplasm,  and  may  or  may  not  contain  the  mi- 
nute spherical  bodies  termed  nucleoli.  In  some  cells  no  nucleus 
can  be  found.     It  may  be  assumed  as  true  that  at  some  period  of 


AUnct'ion-lphtrc  eticlo«ing  two  centtosOEDCS. 


r.i-s(ve  bodKt  (men. 
pljsm  or  Dinplaim) 
suspended  in  the  cy- 
lopMsmic  meshvork 


Fig.  6.  —  Diagram  of  a  cell.     (Wilson.) 


its  life  every  cell  had  a  nucleus,  though  it  may  have  been  lost  in  the 
course  of  development. 

Centrosome.  —  The  centrosome  is  an  extremely  minute  body 
or  pair  of  bodies  usually  surrounded  by  a  mass  of  cytoplasm 
known  as  the  attraction  sphere.  As  a  rule  it  lies  in  the  cytopla.sm, 
not  far  from  the  nucleus,  and  plays  an  important  part  in  nuclear 
division. 

Life  activities  in  cells.  —  Since  the  body  is  composed  of  cells, 
it  follows  that  all  the  activities  of  the  body  are  the  result  of  the 
activities  of  the  cells.  These  activities  produce  changes  in  the 
protoplasm,  the  chief  of  which  may  be  enumerated  as  follows :  — 

(1)  Respiration. — Each  cell  coming  in  contact  with  oxygen 
absorbs  it  and  combines  with  it.     Whenever  this  combination  takes 


Chap.  Ill]  CELLS  23 

place,  a  certain  amount  of  the  protoplasm  is  burned  or  oxidized, 
and  as  a  result  of  this  oxidation  heat  and  other  kinds  of  energy 
are  produced,  and  carbon  dioxide,  which  is  a  waste  product,  is 
evolved.  Thus  it  will  be  seen  that  the  real  purpose  of  respiration 
is  to  furnish  oxygen  to  each  individual  cell,  and  to  take  from  the 
cell  the  carbon  dioxide  which  it  does  not  need. 

(2)  Metabolism.  —  Each  cell  is  able  to  take  to  itself,  and  eventu- 
ally convert  into  its  own  substance,  certain  materials  (foods)  that 
are  non-living ;  in  this  way  the  protoplasm  may  increase  in  amount, 
or  in  other  words,  the  cell  may  grow.  The  amount  of  protoplasm 
is  not  permanently  increased,  because  just  as  much  protoplasm  is 
being  broken  down  by  the  process  of  oxidation,  and  removed  from 
the  cell,  as  is  added  by  the  process  of  assimilation.  Chemical 
changes  which  involve  the  building  up  of  living  material  within 
the  cell  have  received  the  general  name  of  anabolic  changes,  or 
anabolism ;  on  the  other  hand,  those  which  involve  the  breaking 
down  of  such  material  into  other  and  simpler  products  are  known 
as  katabolic  changes,  or  katabolism,  while  the  sum  of  all  the  ana- 
bolic and  katabolic  changes  which  are  proceeding  within  the  cell 
is  spoken  of  as  the  metabolism  of  a  cell.  These  chemical  changes 
are  always  more  marked  as  the  activity  of  the  cell  is  promoted  by 
warmth,  electrical,  or  other  stimulation,  the  action  of  certain  drugs, 
etc. 

(3)  Amosboid  movement.  —  The  most  obvious  physical  changes 
that  can  sometimes  be  seen  in  living  protoplasm,  by  the  aid  of 
the  microscope,  are  those  which  are  termed  "amoeboid."  This 
term  is  derived  from  the  amoeba,  a  single-celled  organism  which 
has  long  been  observed  to  exhibit  spontaneous  changes  of  form, 
accompanied  by  a  flowing  of  its  soft  semi-fluid  substance.  By 
virtue  of  this  property,  the  cells  can  move  from  one  place  to 
another.  If  one  of  these  cells  be  observed  under  a  high-power 
lens  of  the  microscope,  it  will  be  seen  gradually  to  protrude 
a  portion  of  its  protoplasm ;  this  protrusion  extends  itself,  and 
the  main  part  or  body  of  the  cell  passes  by  degrees  into  the 
elongated  protrusion.  By  a  repetition  of  this  process,  the  cell 
may  glide  slowly  away  from  its  original  situation  and  move 
bodily  along  the  field  of  the  microscope,  so  that  an  actual 
locomotion  takes  place.  When  the  surface  of  these  free  cells 
comes  in  contact  with  any  foreign  particles,  the  protoplasm,  by 


24 


ANATOMY  FOR  NURSES 


[Chap.  Ill 


virtue  of  its  amoeboid  movements,  tends  to  flow  round  and  en- 
wrap  the    particles,  and  particles  thus  enwrapped  or  incepted 

may  then  be  conveyed  by 
the  cell  from  one  place  to 
another. 

(4)  Reproduction.  —  Like 
all  living  organisms,  each 
cell  grows,  produces  other 
cells,  and  dies,  so  that  each 
cell  has  a  life  cycle  compa- 
rable to,  but  much  shorter 
than  the  body  itself.  As  the 
cells  are  constantly  dying, 
the  need  for  constant  repro- 
duction is  apparent.  This 
reproduction  is  accomplished 
in  two  ways,  (a)  simple,  di- 
rect division  or  akinesis,  and 
(6)  indirect  division  or  kary- 
okinesis,  which  is  the  almost 
universal  method. 

Fig.  7. -Diagrams  illustrating  division  of  /   )    j      akhiesis    OT   direct 
a  cell.     A,  resting  cell   with  nucleus  (n)  and  ^    '            "       "^          v^l    ^a 
centrosome  (c).     B,  preparing  to  divide,  two  division    the    Cell    cloUgatCS, 
asters  (a)  near  nucleus,  each  with  a  centro-  ,                ,                 1         +      1 
some,  chromatin  becoming  massed  into  chro-  the    nUCleUS  and    Cytoplasm 
mosomes.     C,  two  asters  have  formed  a  spindle  become    COUStrictcd     in     the 
with  chromosomes  (ch)  in  centre.    D,  each  chro- 
mosome divided  and  two  halves  being  moved  centre,    and   the   Ccll  dividcS 
towfird  the  asters.     E,  chromosomes  forming  ■,    «               ,                ii          U*   V. 
the  two  new  nuclei,  and  cell  body  beginning  to  ^"^    lOrmS    tWO    CellS    wnicn 
di\Tde.     F,  division  complete,  two-cell  stage,  ^qqjj  gro^y  tO  the  sizC  of  the 
each  cell  has  the  same  structure  as  the  one  cell  .    .      , 
in  A.     cw,  cell-wall.     (Bigelow  from  Wilson.)  Original  cell. 

(6)  In  karyokinesis  or  in- 
direct division  the  nucleus  passes  through  a  series  of  remarkable 
changes  which  are  rather  complicated.  A  careful  study  of  Fig.  7 
will  give  the  student  some  idea  of  these  changes.^ 

Differences  in  cells.  —  Cells  differ  in  (1)  size,  (2)  form, 
(3)  chemical  composition,  and  (4)  function.  (1)  They  vary  in 
size  from  ^oVo  to  ^^ o^  of  an  inch  (0.008  to  0.08  mm.)  in  diameter.^ 

>  For  a  detailed  description  of  karyokinesis  the  student  is  referred  to  "The  Cell 
in  Development  and  Inheritance,"  by  Wilson. 

'  On  page  469  will  be  found  accurate  ratios  between  the  metric  system  and  the 
system  of  length,  weights,  and  measures  used  in  the  United  States.     For  the  sake 


Chap.  Ill]  ORGAN  25 

(2)  The  simplest  form  of  cell  is  spherical,  but  this  is  seldom  realized 
except  in  unicellular  plants  and  animals.  In  the  human  body  the 
form  of  the  cell  is  modified  by  the  pressure  of  the  surrounding 
structures,  by  active  movements  of  the  cell  substance,  and  by 
growth  and  differentiation.  (3)  It  is  assumed  that  the  marked 
difference  in  the  appearance  of  cells  is  an  expression  of  a  chemical 
difference,  which  in  turn  shows  the  difference  in  function.  (4)  A 
unicellular  animal  is  in  itself  a  complete  living  thing,  and  thus 
one  cell  must  perform  all  the  essential  activities  of  life,  and  is  self- 
sufficient.  In  the  human  animal  the  individual  cells  have  become 
specialized  as  it  were,  and  certain  groups  of  them  perform  certain 
functions,  i.e.  the  function  of  muscle  cells  is  to  contract,  and  the 
combined  contraction  of  a  group  of  muscles  cells  results  in  the 
contraction  of  a  muscle. 

TISSUE 

A  collection  of  cells  of  like  substance  arranged  together  form 
what  is  known  as  a  tissue.  In  many  tissues,  all  the  substance  is 
not  inside  the  cell  walls,  some  of  it  is  between  the  cells  or  inter- 
cellular. In  the  muscles  there  is  a  cement  substance  between  the 
cells  which  holds  them  together.  In  some  tissues  there  is  very 
little  intercellular  substance,  in  others  there  is  a  large  proportion 
of  it. 

ORGAN 

When  two  or  more  different  tissues  are  associated  in  per- 
forming some  special  office  in  the  body,  the  part  so  adapted  is 
termed  an  organ.  Thus,  the  lungs  are  organs  specially  adapted 
for  assisting  in  the  function  of  respiration,  the  bones  are  organs 
adapted  for  support  and  locomotion,  the  kidneys  for  secreting 
urine,  etc.  As  the  structure  of  an  organ  depends  upon  the  prop- 
erties of  the  tissues  composing  it,  so  the  characteristics  of  each 
tissue  depend  upon  their  ultimate  structural  units  —  the  cells 
and  the  intercellular  substance. 

of  simplicity  in  converting  figures  in  the  text,  from  one  system  to  the  other,  we 
have  assumed 

1  cm.  to  equal  |  in.  (25  mm.  =  1  in.). 

1  cc.  to  equal  15  minims. 

30  gm.  to  equal  1  oz.  (dry  or  liquid  measure). 

30  cc.  to  equal  1  oz.  (dry  or  liquid  measure). 

1  litre  to  equal  1.75  pt.  (dry  measure). 

1  litre  to  equal  2.11  pt.  (liquid  measure). 


26  ANATOMY  FOR  NURSES  [Chap.  Ill 

SYSTEM 

An  arrangement  of  organs  closely  allied  to  each  other  and  set 
apart  to  perform  some  general  function  is  spoken  of  as  a  system. 
Eight  systems  are  found  in  the  human  body.  Their  names  with 
the  functions  of  each  are  briefly  expressed  as  follows  :  — 

Skeletal  system.  —  Support  and  locomotion. 

Muscular  system.  —  Irritability  and  motion. 

Vascular  system.  —  Distribution  of  the  body  fluids  to  all  the 
cells. 

Respiratory  system.  —  To  provide  oxygen  and  get  rid  of  carbon 
dioxide. 

Alimentary  system.  —  To  receive,  digest,  and  absorb  the  food 
so  as  to  provide  heat,  energy,  and  materials  to  replace  worn-out 
tissues. 

Excretory  system. — To  eliminate  the  waste  products  that  result 
from  the  activities  of  life. 

Nervous  system.  —  To  control  and  insure  coordination  in  the 
working  of  all  the  systems  in  the  body.  Contains  the  centres  for 
all  the  sensations,  intelligence,  and  thought  that  we  recognize  as 
the  highest  functions  of  life. 

Reproductive  system.  —  To  insure  the  continuance  of  the  race 
by  the  production  of  another  being. 

It  is  important  for  the  student  to  remember  that  these  different 
systems  are  closely  related  and  dependent  on  each  other.  While 
each  forms  a  complete  unit,  specially  adapted  for  the  performance 
of  some  function,  yet  that  function  cannot  be  properly  performed 
without  the  assistance  and  cooperation  of  other  systems.  The 
most  perfect  skeleton  is  not  capable  of  locomotion,  unless  assisted 
by  the  muscular  and  nervous  systems.  Any  interference  with  the 
circulatory  system  also  affects  the  work  of  the  excretory  system, 
etc. 

CLASSIFICATIOX 

By  the  aid  of  the  microscope  the  different  distinct  tissues  of 
which  the  body  is  formed  are  found  to  be  comparatively  few  in 
number,  and  some  of  these,  although  at  first  sight  apparently 
distinct,  yet  have  so  much  in  common  in  their  structure  and  origin, 
one  with  another,  that  the  number  becomes  still  further  reduced, 
until  we  can  distinguish  only  four  distinct  tissues,  viz. :  — 


Chap.  Ill]  EPITHELIAL  TISSUE  27 

1.  The  epithelial  tissues.  3.  The  muscular  tissues. 

2.  The  connective  tissues.  4.  The  nervous  tissues. 
Such  fluids  as  blood  and  lymph  are  frequently  described  as  liquid 
tissues. 

Origin  of  tissues.  —  It  has  been  stated  that  the  cell  is  the  struc- 
tural unit  of  the  body,  and  in  the  beginning  the  body  develops 
from  a  single  cell  named  the  ovum.  The  ovum  is  developed  in  the 
ovary  and  is  made  fertile  by  the  entrance  into  it  of  a  cell,  known 
as  the  spermatozoon  formed  in  the  testes  of  the  male.  After  fertili- 
zation or  impregnation  takes  place,  the  cells  divide  and  subdivide 
until  their  number  is  enormously  increased. 


Fig.  8.  —  Diagrams  to  illustrate  Fertilization  of  an  Egg-cell  (Ovum)  bt  a 
Sperm-cell  (Spermatozoon).  .4,  e,  nucleus  of  a  matured  egg-cell ;  s,  a  sperm-cell 
ready  to  enter.  B,  sperm-cell  entered  and  transformed  into  sperm-nucleus  (s). 
C,  sperm-nucleus  and  egg-nucleus  united,  fertilization  complete.  D,  division  lead- 
ing to  two-cell  stage.     (Bigelow.) 

The  cells  thus  formed  eventually  arrange  themselves  in  the  form  of 
a  membrane,  blastoderm,  which  is  composed  of  three  layers.  These 
layers  are  known  respectively  as  ectoderm,  mesoderm,  and  entoderm. 

The  ectoderm,  or  outer  layer,  forms  the  epidermis  and  the  nervous 
system.  , 

The  mesoderm,  or  middle  layer,  forms  the  circulatory  and  urino- 
genital  systems,  also  the  muscles,  bones,  and  other  connective 
tissues. 

The  entoderm  or  inner  layer  forms  the  greater  part  of  the  alimen- 
tary and  respiratory  tracts,  also  the  liver,  pancreas,  and  other 
glands. 

EPITHELIAL  TISSUE 

Epithelial  tissue  is  composed  entirely  of  cells  united  together 
by  adhesive  matter  or  cement  substance.  The  cells  are  generally 
so  arranged  as  to  form  a  skin,  or  membrane,  covering  the  external 
surfaces,  and  lining  the  internal  parts  of  the  body.  This  mem- 
brane is  seen  when  the  skin  is  blistered,  the  thin  and  nearly 


28 


ANATOMY  FOR   NURSES 


[Chap.  IU 


transparent  membrane  raised  from  the  surface  being  epithelial 
tissue  —  in  this  situation  called  epidermis,  because  it  lies  upon 
the  surface  of  the  true  skin.  In  other  situations,  epithelial 
tissue  usually  receives  the  general  name  of  epithelium. 

We  may  classify  the  varieties  of  epithelium  according  to  the 
shape  of  the  cells  which  compose  them,  or  according  to  the  arrange- 
ment of  these  cells  in  layers.  Adopting  the  latter  and  simpler 
classification,  we  distinguish  three  main  varieties  :  — 

1.  The  simple,  consisting  of  a  single  layer  of  cells. 

2.  The  transitional,  consisting  of  two  or  three  layers. 

3.  The  stratified,  consisting  of  many  layers. 

1.  Simple  epithelium.  — This  is  composed  of  a  single  layer  of 
cells.  The  cells  forming  single  layers  are  of  distinctive  shape, 
and  have  distinctive  functions  in  different  parts  of  the  body.  The 
chief  varieties  are  :  — 

a.  pavement  b.  columnar  c.  ciliated 

(a)  Pavement  epithelium.  —  This  is  also  called  squamous  or 
scaly  epithelium.  The  cells  form  flat,  many-sided  plates  or  scales, 
which  fit  together  like  the  tiles  of  a  mosaic 
pavement.  It  forms  very  smooth  surfaces, 
and  lines  the  heart,  blood-vessels,  and  lym- 
phatics, the  mammary  ducts,  the  serous 
cavities,  etc. 

(6)  Columnar  epithelium. — The  colum- 
nar epithelium  is  a  variety  of  simple  epi- 
thelium in  which  the  cells  have  a  prismatic 
shape,  and  are  set  upright  on  the  surface 
which  they  cover.  In  profile  these  cells  look  somewhat  like  a 
close  palisade.  They  taper  somewhat  toward  their  attached  end, 
which  is  set  upon  a  basement  membrane. 
Columnar  epithelium  is  found  in  its  most 
characteristic  form  lining  the  intestinal 
canal. 

(c)  Ciliated  epithelium.  —  In  ciliated  epi- 
thelium the  cells,  which  are  generally  colum- 
nar in  shape,  bear  at  their  free  surface  little 
hair-like  processes   (strongly  suggestive  of 

eyelashes) ,  which  are  agitated  incessantly  with  a  lashing  or  vibrat- 
ing motion.     These  minute  and  delicate  processes  are  named  cilia, 


Fig.  9.  —  Simple  Pave- 
ment Epithelium.  a, 
from  a  serous  membrane ; 
6,  from  a  blood-vessel. 


Fig.  10. — Simple  CoL- 

UMN.\R     EpITHELIU.M.       O, 

the  cells  ;  b,  intercellular 
substance  between  the 
lower  end  of  cells. 


Chap.  Ill] 


EPITHELIAL  TISSUE 


29 


and  may  be  regarded  as  active  prolongations  of  the  cell-pro- 
toplasm. The  manner  in  which  cilia  move  is  best  seen  when 
they  are  not  acting  very 
quickly.  The  motion  of  an 
individual  cilium  may  be 
compared  to  the  lash-like 
motion  of  a  short-handled 
whip,  the  cilium  being  rap- 
idly bent  in  one  direction. 
The  motion  does  not  involve 
the  whole  of  the  ciliated  sur- 
face at  the  same  moment, 
but  is  performed  by  the  cilia 
in  regular  succession,  giving 
rise  to  the  appearance  of  a 
series  of  waves  travelling  along  the  surface  like  the  waves  tossed 
by  the  wind  in  a  field  of  wheat.  When  they  are  in  very  rapid  ac- 
tion, their  motion  conveys  the  idea  of  swiftly  running  water.  As 
they  all  move  in  one  direction,  a  current  of  much  power  is  produced. 

Function.  —  Cilia  have  been  shown  to  exist  in  almost  ever}'  class 
of  animal,  from  the  highest  to  the  lowest.  In  man  their  use  is  to 
impel  secreted  fluids,  or  other  matters,  along  the  surfaces  to  which 
they  are  attached ;  as,  for  example,  the  mucus  of  the  trachea  and 
nasal  chambers,  which  they  carry  toward  the  outlet  of  these  pas- 
sages, and  thus  keep  out  foreign  matter. 

2.  Transitional  epithelium.  —  This  consists  of  two  or  three 
layers  of  cells.  The  superficial  cells  are  large  and  flattened,  having 
on  their  under  surface  depressions  into  which  fit  the  larger  ends  of 


Fig.  11.  —  Ciliated  Epithelium  from 
THE  Human  Trachea.  (Highly  magnified.) 
a,  large  eUiated  cell ;   d,  cell  with  two  nuclei. 


Fig.  12.  —  Sectiox  of  the  Transitional  Epithelium  lining  the  Bladder. 
(Highly  magnified.)  o,  superficial ;  6,  intermediate ;  c,  deep  layer  of  cells. 
(Schafer.) 


30  ANATOMY  FOR  NURSES  [Chap.  Ill 

the  pear-shaped  cells  which  form  the  next  layer.  Between  the 
tapering  ends  of  these  pear-shaped  cells  are  one  or  two  layers 
of  smaller,  many-sided  cells,  the  epithelium  being  renewed  by 
division  of  these  deeper  cells.  This  kind  of  epithelium  lines  the 
bladder  and  ureters. 

3.  Stratified  epithelium.  —  This  consists  of  main'  layers  of  cells. 
The  cells  composing  the  different  layers  differ  in  shape.  As  a  rule, 
the  cells  of  the  deepest  layer  are  columnar  in  shape ;  the  next, 
rounded  or  many-sided,  whilst  those  nearest  the  surface  are  always 
flattened  and  scale-like.  The  deeper  soft  cells  of  a  stratified 
epithelium  are  separated  from  one  another  by  a  system  of  channels, 
which  are  bridged  across  by  numerous  fibres.  These  cells  are  often 
described  as  prickle  cells,  as  when  separated  they  appear  beset  with 
spines.  They  are  continually  multiplying  by  cell-division,  and  as 
the  new  cells  which  are  thus  produced  in  the  deeper  parts  increase 
in  size,  they  compress  and  push  outward  those  previously  formed. 


Fig.  13.  —  Section  of  Stratified  Epitheliu.m.  c,  lowermost  columnar  cells; 
P,  polygonal  cells  above  these ;  fl.,  flattened  cells  near  the  surface.  Between  the 
cells  are  seen  intercellular  channels,  bridged  over  by  processes  which  pass  from  cell 
to  cell.     (Schafer.) 

In  this  way  cells  which  were  at  first  deeply  seated  are  gradually 
shifted  outward  and  upward,  growing  harder  as  they  approach  the 
surface.  The  older  superficial  cells  are  being  continually  rubbed 
off  as  the  new  ones  continually  rise  up  to  supply  their  places. 

Stratified  epithelium  covers  the  anterior  surface  of  the  eye, 
lines  the  mouth,  the  chief  part  of  the  pharynx,  the  oesophagus,  the 
anal  canal,  part  of  the  urethra,  and  in  the  female  the  vagina  and 
neck  of  the  uterus. 

Its  most  extensive  distribution  is  over  the  surface  of  the  skin, 
where  it  forms  the  epidermis.  Whenever  a  surface  is  exposed 
to  friction,  we  find  stratified  scaly  epithelium,  and  we  may  there- 
fore classify  it  as  a  protective  epithelium. 


Chap.  Ill]  EPITHELIAL  TISSUE  31 

Function.  —  The  most  important  functions  of  epithelial  tissue 
are  as  follows : 

1.  Protection.  —  Some  varieties  are  specially  modified  so  as  to 
form  protective  membranes.  Example  — •  skin.  Other  varieties 
form  the  top  layer  of  the  mucous  membranes,  and  mucous  mem- 
branes are  found  lining  passages  that  communicate  with  the  ex- 
terior of  the  body.  Serous  membranes  are  also  lined  by  epithelial 
cells.  These  serous  membranes  line  passages  that  do  not  com- 
municate w4th  the  exterior  of  the  body. 

2.  Motion.  —  This  is  seen  in  the  cilia,  which  tend  to  keep  the 
passages  to  w^hich  they  are  attached  clean,  and  free  from  foreign 
material. 

3.  Absorption.  —  This  is  particularly  well  seen  in  the  digestive 
tract.     To  some  extent  the  skin  also  is  capable  of  absorption. 

4.  Secretion.  —  Every  secreting  organ  must  contain  epithelial 
cells.  Mucous  and  serous  membranes  are  examples  of  secreting 
organs. 

5.  Special  Sensation.  —  The  organs  of  the  special  senses  contain 
epithelial  cells.     Examples  —  eye,  ear,  nose,  etc. 


32 


ANATOMY  FOR  NURSES 


[Chap.  Ill 


SUMMARY 


Life  activities  in 
cells 


1.   Respiration 


The  Human  body  is  an  enormous  aggregate  of  cells. 

Cell  membrane  —  may  or  may  not  be  present. 

C^loplasm  —  distinctive  name  given  to  protoplasm  that 
surrounds  nucleus. 

Nucleus  —  a  more  solid  central  portion  surrounded  by 
a  membrane.  The  protoplasm  of  the  nucleus  is 
Cell    .     .     .     .    ]     called  karyoplasm. 

Nucleolus  ^  minute,  spherical  bodies  found  in  nucleus. 

Centrosome  —  one  or  two  extremely  small  bodies,  sur- 
rounded by  attraction  sphere,  which  is  made  up  of 
cytoplasm.     Alwaj's  located  near  nucleus. 

(Combines  with  oxygen  =  oxidation. 
Liberates  heat. 
Carbon  dioxide  formed. 
I  Anabolism  =  building  up  process. 
1  Katabohsm  =  breaking  down  process. 
Amoeboid  movements. 

fAkincsis  or  direct  division. 
1  Karyokincsis  or  indirect  division. 
Size  y^Vr?  to  ^^  of  an  inch  (0.008  to  0.08  mm.). 

{Pressure. 
Movements 'of  cell. 
Growth  and  differentiation. 
cells  1  Chemical  composition  —  dependent  on  special  work  of 

cell. 
Function  —  assist  in  work  of  tissue  or  organ  of  wliich 
it  forms  a  part. 


Metabohsm 


Reproduction 


Tissues 


Organs 


-  are  made  up  of  a  collection  of  cells  of  like  substance,  with 
more  or  less  intercellular  substance  between  the  cells. 

are  made  up  of  two  or  more  tissues  associated  to  perform  a 
common  function. 

Sj'stem  —  a  group  of  organs  set  apart  to  perform  some 

special  function. 
Skeletal         1 
Muscular 


System 


\  Vascular 
Respiratory 
AUmentary 
Excretory 
Nervous 


All  interdependent. 


Classification   offl.   Epithelial, 
tissues  1 2.   Connective. 


3.  Muscular. 

4.  Nervous. 


Chap.  Ill] 


SUMMARY 


33 


Origin  of  tissues 


I  Imprei 


gnation  —  Multiplica- 
tion of  cells  —  Blastoderm 


Entoderm 


(Epidermis. 
NerVous 
system. 
Circulatory. 

system. 
Urino-gcni- 

Mesoderm  \     tal  system. 
I      tion  ot  ceils  —  tsiastoderm  ^yr      , 

Connective 
tissues. 

Respiratory 
tract. 

Alimentary 
tract. 

Liver,  Pan- 
creas. 

Epithelial  —  a  tissue  of  cells  and  little  intercellular  substance. 

(Pavement  or  scaly. 
Columnar. 
Ciliated. 
Transitional,  consisting  of  2  or  3  layers. 
.Stratified,  consisting  of  many  layers. 

Protection. 
Motion. 
Absorption. 
Secretion. 
.Special  sensation. 


Classification  of 
Epithelial 
Tissue 


Function 


CHAPTER   IV 

CONNECTIVE   TISSUES:    AREOLAR,   FIBROUS,   ELASTIC,   ADIPOSE, 
RECTICULAR,   LYMPHOID,    CARTILAGE,   BONE 

Following  the  classification  of  tissues  we  have  adopted,  the 
next  group  to  be  studied  is  that  known  as  the  connective  tissue 
group. 

Our  description  of  epitheHal  tissue  was  briefly  this :  a  skin  or 
membrane  formed  of  cells,  which  cells  may  be  of  a  variety  of 
shapes,  and  be  arranged  in  one  or  more  layers.  It  is  distinctly 
a  tissue  of  cells  with  very  little  of  what  we  call  intermediate  or 
intercellular  substance  lying  between  the  cells.  Connective 
tissue  differs  from  epithelial  tissue  in  having  a  great  deal  of  inter- 
cellular substance  lying  between  the  cells.  It  may  be  interesting 
to  note  that  in  this  form  of  tissue,  the  intercellular  substance  is 
supposed  to  develop  from  the  cells. 

CONNECTIVE   TISSUE  GROUP 

These  tissues  differ  considerably  in  their  external  characteristics, 
but  are  alike  (1)  in  that  they  all  serve  to  connect  and  support  the 
other  tissues  of  the  body;  (2)  they  are  all  developed  from  the 
mesoderm ;  (3)  the  cellular  element  is  at  a  minimum,  and  the 
intercellular  material  is  at  a  maximum ;  (4)  they  originate  no 
action,  but  are  acted  upon  by  the  other  tissues.  We  may  there- 
fore group  them  together  as  follows  :  — 

1 .  Areolar  tissue.  5.  Reticular  tissue. 

2.  Fibrous  tissue.  6.  Lymphoid  tissue. 
8.  Elastic  tissue.  7.  Cartilage. 

4.  Adipose  tissue.  8.  Bone  or  osseous  tissue. 

Areolar  tissue.  —  This  tissue  appears  to  l)e  composed  of  a 
multitude  of  fine  threads  or  films,  called  fibres.  Viewed  with 
a  microscope,  these  fibres  are  seen  to  be  principally  made  up  of 
wavy  bundles  of  exquisitely  fine,  transparent,  white  fibres,  and 
these  bundles  intersect  in  all  directions.     Mixed  with  the  white 

34 


Chap.  IV] 


CONNECTIVE  TISSUES 


35 


fibres  are  a  certain  number  of  yellow  elastic  fibres,  which  do  not 
form  bundles,  and  have  a  straight  instead  of  a  wavy  outline. 
Between  these  fibres  are  open  spaces,  called  areolae,^  that  com- 
municate freely  with  one  another.  Lying  in  the  areolae  between  the 
bundles  of  fibres  are  seen  the  tissue-cells,  of  which  there  are 
many  varieties. 

If  we  make  a  cut  through  the  skin  of  some  part  of  the  body 
where  there  is  no  subcutaneous  fat,  as  in  the  upper  eyelid,  and 
proceed  to  raise  it  from  the  parts  lying  beneath,  we  observe  that 


Fig.  14.  —  Subcutaneous  Areolar  Tissue  from  a  Young  Rabbit.  (Highly 
magnified.)  The  white  fibres  are  in  wavy  bundles,  the  ela.stic  fibres  form  an  open 
network,  p,  p,  vacuolated  cells ;  g,  granular  cell ;  c,  c,  branching  lamellar  cells ; 
c',  a  flattened  cell,  of  which  only  the  nucleus  and  some  scattered  granules  are  visi- 
ble;    /,  fibrillated  cell.     (Schafer.) 

it  is  loosely  connected  to  them  by  a  soft,  filmy  substance  of  con- 
siderable tenacity  and  elasticity.     This  is  areolar  tissue. 

Fibrous  tissue.  —  This  tissue  is  intimately  allied  in  structure  to 
the  areolar  tissue.  It  consists  almost  wholly  of  wavy  white  fibres, 
which  cohere  very  closely  and  are  arranged  side  by  side  in  bundles 
which  have  an  undulating  outline.  The  spaces  between  the 
bundles  are  occupied  by  cells  arranged  in  rows,  but  the  cells  are 

1  Areola  is  the  Latin  word  for  "  a  small  space."  Areolar  tissue  gets  its  name  from 
appearing  full  of  minute  spaces. 


36  ANATOIMY  FOR  NURSES  [Chap.  IV 

not  a  prominent  feature  of  this  tissue.    The  fibres  may  be  some 

inches  long,  do  not  branch,  and  confer  a  distinctly  fibrous  aspect 

on  the  parts  which  they  compose. 

'  '  ■  Fibrous   tissue  is  white,  with  a 

^  ,^,  ^    peculiarly  shining,    silvery   aspect. 

It  is  exceedingly  strong  and  tough, 

yet  perfectly  pliant ;  but  it  is  almost 

devoid  of  extensibilitv  and  is  very 

1^'  I         sparingly  supplied  with  nerves  and 

j  blood-vessels. 

j  Elastic  tissue.  —  In  elastic  tissue 

Q       '  I  the  wavj'  white  bundles  are  com- 

^-  !  paratively  few  and  indistinct,  and 

:  there  is  a   proportionate  develop- 

,.   /  ment  of  the  elastic  fibres.     When 

present  in  large  numbers,  they  give 

a  yellowish  color  to  the  tissue.    This 

Fig.  15.  — Fibrocs  Tissue,  from  form  of  connective  tissue  is  extensile 
THE    Longitudinal    Section   of  a  ,      ,       .      .         i        i  •   i 

Tendon.    The  spaces  between  the  and  elastic  in  the  highest  degree, 

Te'^:.'''tiZ:iZ\T'^'''''"^'  ^^^   wherever  located,  .does   such 

work  as  India  rubber  would  do. 
It  is  not  so  strong  as  the  fibrous  variety,  and  breaks  across 
the  direction  of  its  fibres  wiien  forcibly  stretched. 

Function.  —  These  three  varieties  of  connective  tissue  (areolar, 
fibrous,  clastic)  agree  closely  with  one  another  in  elementary 
structure.  It  is  the  different  arrangement  of  the  cells  and  fibres, 
and  the  relative  proportion  of  one  kind  of  fibre  to  the  other,  that 
gives  them  their  different  characteristics.  They  are  used  for  purely 
mechanical  purposes. 

Areolar  tissue  forms  web-like  binding  and  supporting  material 
and  serves  to  connect  and  insulate  entire  organs.  It  is  one  of  the 
most  general  and  most  extensively  distributed  of  the  tissues. 
It  is,  moreover,  continuous  throughout  the  body,  and  from  one 
region  it  may  be  traced  without  interruption  into  any  other,  how- 
ever distant,  —  a  fact  not  without  interest  in  practical  medicine, 
seeing  that  in  this  way  air,  water,  pus  and  other  fluids,  effused 
into  the  areolar  tissue,  may  spread  far  from  the  spot  where  they 
were  first  introduced  or  deposited. 

Fibrous  tissue  is  met  with  in  the  form  of :  — 


Chap.  IV]  CONNECTIVE  TISSUES  37 

(1)  Ligaments.  —  Ligaments  are  strong  flexible  bands,  or  cap- 
sules, of  fibrous  tissue  that  help  to  hold  the  bones  together  at  the 
joints. 

(2)  Tendons  or  sinews.  —  Tendons  are  white  glistening  cords  or 
bands  which  serve  to  attach  the  muscles  to  the  bones.  They  are 
usually  composed  of  white  fibres,  but  may  contain  some  yellow 
fibres. 

(3)  Aponeuroses.  —  Aponeuroses  are  flat,  wide  bands  of  fibrous 
tissue  which  serve  to  connect  one  muscle  with  another. 

(4)  Protecting  sheaths  or  membranes.  —  Fibrous  tissue  is  found 
investing  and  protecting  different  organs  of  the  body.  Examples 
—  heart  and  kidneys. 

(5)  Fascioe.  —  The  word  fascia  means  a  band  or  bandage.  It  is 
most  frequently  applied  to  sheets  of  fibrous  membrane  which  are 
wrapped  around  muscles,  and  serve  to  hold  them  in  place.  Fas- 
ciae are  divided  into  two  groups,  which  are  associated  with  the  skin 
and  the  muscles.     They  are  called  :  — 

a.  Superficial. 

h.  Deep. 

a.  Superficial  fascia.  - — The  subcutaneous  areolar  tissue,  which 
forms  a  nearly  continuous  covering  beneath  the  skin,  is  classed  as 
superficial  fascia.  It  varies  in  thickness,  and  usually  permits  free 
movement  of  the  skin  on  the  subjacent  parts. 

The  fascia  covering  the  palms  of  the  hands  is  named  palmar 
fascia,  and  the  fascia  covering  the  soles  of  the  feet  is  named  plantar 
fascia.  The  palmar  and  plantar  fascia  are  much  thicker,  stronger, 
and  more  closely  attached  than  the  superficial  fascia  in  other  parts 
of  the  body. 

6.  Beep  fascice.  —  The  deep  fasciae  are  sheets  of  white,  flexible 
fibrous  tissue,  employed  to  envelop  and  bind  down  the  muscles, 
also  to  separate  them  into  groups.  The  term  fascia,  unless  limited 
by  an  adjective,  is  usually  employed  to  designate  the  deep  fascial. 
Subcutaneous  areolar  tissue  is  rarely  called  by  the  name  fascia, 
though  it  is  correctly  classed  as  such. 

Elastic  tissue,  being  extensile  and  elastic,  has  a  most  important 
use  in  assisting  muscular  tissue,  and  so  lessening  the  wear  and  tear 
of  muscle.     It  is  found  :  — 

(1)  Between  the  transverse  processes  of  the  vertebra  in  elastic 
bands.     (Ligamenta  flava.) 


38 


ANATOMY   FOR   NURSES 


[Chap.  IV 


(2)  In  the  walls  of  the  blood-vessels  (especially  arteries),  air 
tubes,  and  vocal  cords. 

(3)  Entering'  into  the  formation  of  the  lungs  and  uniting  the 
cartilages  of  the  laryn.x. 

Adipose  tissue.  —  When  fat  begins  to  be  formed,  it  is  deposited 
in  tiny  droplets '  in  some  of  the  cells  of  the  areolar  tissue ;   these 


Fig.  16.  —  A  Few  Fat  Cells  fkom  the  Margin  of  a  F.\t  Lobule.  (Very 
hiRhly  magnified.)  f.g.  fat  globules  distending  a  fat  cell ;  n,  nucleus ;  w,  membra- 
nous envelope  of  the  fat  cell ;  c,  capillary  vessel ;  v,  veinlet ;  c.l.  connective-tissue 
cell ;    the  fibres  of  the  connective  tissue  are  not  shown.      (Schafer.) 

droplets  increase  in  .size,  and  eventually  run  together  so  as  to  form 
one  large  drop  in  each  cell.  By  further  deposition  of  fat  the  cell 
becomes  swollen  out  to  a  size  far  beyond  that  which  it  possessed 
originally,  until  the  protoplasm  remains  as  a  delicate  envelope 
surrounding  the  fat  drop.  The  nucleus  is  crowded  off  to  one  side 
and  attached  to  the  cell  wall.  As  these  cells  increase  in  number 
they  collect  into  small  groups  or  lobules,  which  lobules  are  for  the 
most  part  lodged  in  the  meshes  of  the  areolar  tissue,  and  are  also 
supported  by  a  fine  network  of  blood-vessels.  This  fatty  tissue 
exists  very  generally  throughout  the  body,  accompanying  the  still 
more  widely  distributed  areolar  tissue  in  most  parts,  though  not 
in  all,  in  which  the  latter  is  found.     Still,  its  distribution  is  not 

•  The  contents  of  the  fat  cells  of  adipose  tissue  are  fluid  during  life,  as  the  normal 
temperature  of  the  body  is  considerably  above  the  melting  point  of  the  mixture 
of  fats  found  there. 


Chap.  IV]  CONNECTIVE  TISSUES  39 

uniform,  and  there  are  some  situations  in  which  it  is  collected 
more  abundantly.     This  tissue  is  found  chiefly  :  — 

(1)  Underneath  the  skin,  in  the  subcutaneous  layer. 

(2)  Beneath  the  serous  membranes  or  in  their  folds. 

(3)  Collected  in  large  quantities  around  certain  internal  organs, 
especially  the  kidneys,  which  it  helps  to  hold  in  place. 

(4)  Filling  up  furrows  on  the  surface  of  the  heart. 

(5)  As  padding  around  the  joints. 

(6)  In  large  quantities  in  the  marrow  of  the  long  bones. 
Function.  —  Adipose  tissue  serves  several  important  purposes. 

(1)  Unless  formed  in  abnormal  quantities  it  confers  graceful  out- 
lines. (2)  It  constitutes  an  important  reserve  fund,  which  when 
required  can  be  returned  to  the  blood  and  oxidized,  thus  producing 
heat  and  energy.  (3)  It  serves  as  a  jacket  or  covering  under  the 
skin,  and  being  a  non-conductor  of  heat,  prevents  the  too  rapid 
loss  of  heat  through  the  skin.  (4)  It  is  an  admirable  packing 
material,  and  serves  to  fill  up  spaces  in  the  tissues,  and  thus  af- 
fords support  for  delicate  structures  such  as  blood-vessels  and 
nerves. 

Reticular  or  retiform  ^  tissue.  — This  variety  of  connective  tissue 
consists  of  a  close  network  of  white  fibres  with  few,  if  any,  yellow. 


Fig.  17.  —  Retiform  Tissue  from  a   Lymph    Node,     r,    r,    r,   represent    ope^ 
meshes  of  this  tissue.     (Quaiii.) 

fibres.  The  meshes  of  the  network  are  small  and  close  in  sOme 
parts,  more  open  and  like  areolar  tissue  in  other  parts.  The  fibres 
are  nearly  covered  by  fibrous  tissue  cells  in  the  form  of  broad^  thin 

1  Reticulum  (from  the  Latin  reticulum  "a  small  net").      Resembling  a  small 
net. 


40 


ANATOMY  FOR  NURSES 


[Chap.  IV 


plates  wrapped  around  them.  It  forms  a  fine  framework  in  many 
organs. 

Lymphoid  or  adenoid  '  tissue.  —  This  is  reticular  tissue  in  which 
the  meshes  of  the  network  are  occupied  by  lymph  corpuscles. 
This  is  the  most  common  condition  of  retiform  tissue. 

Function.  —  Lymphoid  tissue  forms  the  principal  part  of  the 
substance  of  the  spleen  and  lymph  nodes.  It  also  enters  into  the 
composition  of  the  tonsils  and  some  of  the  intestinal  glands. 

Cartilage.  —  This  is  the  well-known  substance  called  "  gristle." 
Although  cartilage  can  be  readily  cut  with  a  sharp  knife,  it  is  never- 
theless of  very  firm  consistence,  but  at  the  same  time  highly  elastic, 

so  that  it  readily  yields  to  exten- 
sion or  pressure,  and  immediately 
recovers  its  original  shape  when 
the  constraining  force  is  with- 
drawn. When  a  very  thin  section 
is  examined  with  a  microscope,  it 
is  seen  to  consist  of  nucleated  cells 
disposed  in  small  groups  in  a  mass 
of  intercellular  substance.  This 
intercellular  substance  is  some- 
times transparent,  and  to  all  ap- 
pearances structureless ;  some- 
times it  is  pervaded  with  white 
fibres  and  sometimes  with  yellow 
fibres.  According  to  the  amount 
and  texture  of  the  intercellular 
substance,  we  distinguish  three 
principal  varieties :  — 

(1)  Hyaline  or  true  cartilage. 

(2)  White  fibro-cartiloge. 

(3)  Yellow  or  elastic  fihro-cartilage. 
Hyaline  cartilage.  —  This  variety  is  named  from  the  Greek 

word  for  glass.  A  comparatively  small  number  of  cells  are  em- 
bedded in  an  abundant  quantity  of  intercellular  substance  which 
has  the  appearance  of  ground  glass. 

White  fibro-cartilage.  —  The  intercellular  substance  is  pervaded 


Z.  SAILS 


Fio.  18.  —  Articular  Hyaline 
Cartilage  from  the  Femur  of  an 
Ox.  s,  intercellular  substance;  p,  pro- 
toplasmic cell ;  n,  nucleus.     (Ranvier.) 


1  Adenoid  (from  the  Greek  aden,  "a  gland,"  and  eiodos,  "  form"  or  "resemblance." 
Pertaining  to  or  resembling  a  gland. 


Chap.  IV]  CONNECTIVE  TISSUES  41 

with  bundles  of  white  fibres,  between  which  are  scattered  cartilage 
cells.  It  closely  resembles  white  fibrous  tissue,  and  is  found 
wherever  great  strength,  combined  with  a  certain  amount  of  rigid- 
ity, is  required. 

Yelloiv,  or  elastic,  fibro-cartilage.  —  The  intercellular  substance 
is  pervaded  with  yellow  elastic  fibres  which  form  a  network. 
In  the  meshes  of  the  network  the  cartilage  cells  are  found. 

Function.  —  The  function  of  cartilage  is  roughly  the  same 
throughout,  the  qualifying  terms  are  used  to  denote  differences  in 
structure  and  appearance  rather  than  in  function. 

1.  Hyaline  cartilage  covers  the  ends  of  the  bones  in  the  joints, 
where  it  is  known  as  articular  cartilage. 

2.  Hyaline  cartilage  forms  the  rib  cartilages,  where  it  is  known 
as  costal  cartilage. 

In  both  these  situations  the  cartilages  are  in  immediate  connec- 
tion with  bone,  and  may  be  said  to  form  part  of  the  skeleton, 
hence  frequently  described  as  skeletal  cartilages. 

The  articular  cartilages,  in  covering  the  ends  or  surfaces  of 
bones  in  the  joints,  provide  these  harder  parts  with  a  thick,  springy 
coating,  which  breaks  the  force  of  concussion,  and  gives  ease  to 
the  motion  of  the  joint.  The  costal  cartilages,  in  forming  part  of 
the  solid  framework  of  the  thorax  or  chest,  impart  elasticity  to  its 
walls.  Hyaline  cartilage  also  enters  into  the  formation  of  the  nose, 
ear,  larynx,  and  trachea.  It  strengthens  the  substance  of  these 
parts  without  making  them  unduly  rigid,  maintains  their  shape, 
keeps  open  the  passages  through  them  where  such  exist,  and  gives 
attachment  to  moving  muscles  and  connecting  ligaments. 

White  fibro-cartilage  is  found  joining  bones  together,  the  most 
familiar  instance  being  the  flat,  round  plates  or  disks  of  fibro- 
cartilage  connecting  the  bones  of  the  spine  and  the  pubic  bones. 
In  these  cases  the  part  in  contact  with  the  bone  is  alw^ays  hyaline 
cartilage,  which  passes  gradually  into  the  fibro-cartilage. 

Yellow,  or  elastic,  fibro-cartilage  is  found  in  the  epiglottis,  carti- 
lages of  the  larynx.  Eustachian  tube,  and  external  ear. 

Cartilage  is  not  supplied  with  nerves,  and  very  rarely  with 
blood-vessels.  Being  so  meagrely  supplied  with  blood,  the  vital 
processes  in  cartilage  are  very  slow,  and  when  a  portion  of  it  is 
absorbed  in  disease  or  removed  by  the  knife,  it  is  regenerated 
very  slowly.     A  wound  in  cartilage  is  usually  at  first  healed  by 


42  ■  ANATOMY   FOR  NURSES  [Chap.  IV 

connective  tissue  proper,  which  may  or  may  not  become  grad- 
ually transformed  into  cartilage.  Nearly  all  cartilages  receive 
tiieir  nourishnuMit  from  the  perichondrium  which  covers  them, 
and  which  is  a  moderately  vascular  fil)r()us  membrane. 

Bone,  or  osseous  tissue.  —  Bone  is  connective  tissue  in  which 
the  intercellular  substance  which  is  derived  from  the  cells  is 
rendered  hard  by  being  impregnated  with  mineral  salts. 

The  mineral,  or  earthy,  substance  which  is  deposited  in  bone, 
and  which  makes  it  hard,  consists  chiefly  of  phosphate  of  calcium, 
with  about  a  fifth  part  of  carbonate  of  calcium,  and  a  small 
portion  of  other  salts. 

The  organic,  or  soft,  matter  consists  chiefly  of  blood-vessels  and 
connective  tissue,  and  may  be  resolved  by  boiling  almost  entirely 
into  gelatine. 

It  is  possible  to  separate  each  of  these  substances.  The  min- 
eral matter  may  be  removed  by  soaking  a  bone  in  dilute  acid  for 
several  days.  The  result  will  be  a  tough,  flexible,  elastic  substance, 
consisting  only  of  organic  matter.  The  shape  of  the  bone  will  be 
preserved,  but  the  specimen  will  be  so  free  from  stiffness  that  it 
may  be  tied  in  a  knot. 

The  organic  matter  may  be  driven  off  by  heat.  As  before,  the 
shape  of  the  bone  will  be  preserved.  The  specimen  will  consist 
only  of  mineral  matter,  will  appear  white,  rigid,  and  so  brittle  it 
can  bo  crushed  between  the  fingers. 

Amount  of  organic  and  inorganic  matter.  —  The  comparative 
amount  of  organic  and  inorganic  matter  found  in  bone  is  dependent 
on  the  age  of  the  individual.  In  the  foetus  the  tissues  that  later 
become  bone  are  either  fibrous  or  cartilaginous.  By  absorption 
of  mineral  substances  from  the  blood,  these  tissues  gradually 
become  ossified.  Thus  it  follows  that  in  youth  the  organic  matter 
is  in  excess.  In  adult  life  the  organic  matter  constitutes  about 
one-third  of  the  weight  of  the  bone,  and  the  inorganic  matter 
two-thirds.     In  old  age  the  amount  of  inorganic  matter  is  increased. 

Fractiure.  —  The  term  "fracture"  is  applied  to  the  breaking  of  a 
bone.  As  a  result  of  the  greater  amount  of  organic  matter  in  the 
bones  of  children,  they  are  flexible,  bend  easily,  and  do  not  break 
readily.  In  some  cases  the  bone  bends  like  a  bough  of  green  wood. 
Some  of  the  fibres  may  break,  but  not  the  whole  bone,  hence  the 
name  "  green-stick  fracture."     It  is  also  true  that   the  greater 


Chap.  IV] 


CONNECTIVE  TISSUES 


43 


"^'mm 


amount  of  inorganic  matter  in  the  bones  of  the  aged  renders  the 
bones  more  brittle,  so  that  they  break  easily  and  heal  with  diflSculty. 

Rachitis  or  Rickets.  —  In  the  disease  called  rickets,  quite  com- 
mon among  poorly  nourished  children,  there  is  not  sufficient  min- 
eral matter,  so  that  the  bones  are  flexible,  bend 
easily,  and  may  be  permanently  misshapen. 

Structure  of  Bone.  —  On  sawing  a  bone  it 
will  be  seen  that  in  some  parts  it  is  open  and 
spongy,  whilst  in  others  it  is  dense  and  close 
in  texture,  appearing  like  ivory.  We  thus  dis- 
tinguish two  forms  of  bony  tis  sue  :  — 

(1)  The  cancellated,  or  spongy. 

(2)  The  dense,  or  compact. 
On  closer  examination,  however,  it  will  be 

seen  that  the  bony  matter  is  everywhere  po- 
rous, and  that  the  difference  between  the  two 
varieties  of  tissue  arises  from  the  fact  that  the 
compact  tissue  has  fewer  spaces  and  more 
solid  matter  between  them,  while  the  can- 
cellated has  larger  cavities  and  more  slender 
intervening  bony  partitions.  In  all  bones 
the  compact  tissue  is  the  stronger ;  it  lies  on 
the  surface  of  the  bone  and  forms  an  outer 
shell  or  crust,  whilst  the  lighter,  spongy  tissue 
is  contained  within.  The  shafts  of  the  long 
bones  are  almost  entirely  made  up  of  the  com- 
pact substance,  except  that  they  are  hollowed  » u 
out  to  form  a  central  canal,  —  the  medullarv  j  I 
canal,  —  which  has  a  fibrous  lining  called  en-  z  e 
dosteum,  and  contains  marrow.  ^ 

The  hard  substance  of  both  varieties  is  ar- 
ranged in  bundles  of  bony  fibres,  or  lamellae 
(layers) .  Fig.  19.  —  Vertical 

T  11         1  u  1        Section    of    a    Long 

Cancellated  bone.  —  In  cancellated  bone  the  bone.    (Gerrish.) 
lamellae  join  and  meet  together  so  as  to  form 
a  structure  resembling  lattice- work  {cancelli),  whence  this  tissue 
receives  its  name.     In  the  interstices  of  this  kind  of  bone  we  find 
the  blood-vessels  supported  by  the  marrow. 

Compact  bone. — In  compact  bone  the  lamellae  are  usually  arranged 


f\ 


^SS 


44  ANATOMY   FOR   NURSES  [Chap.  IV 

in  rings  around  canals,  —  Haversian  canals,  —  which  carry  blood- 
vessels in  a  longitudinal  direction  through  the  bones.  Between  the 
lamellae  are  branciied  cells  which  lie  in  cell-spaces,  or  cavities,  called 
lacunae  (little  lakes),  and  running  out  in  a  wheel-like  or  radial  di- 
rection from  each  lacuna  are  numerous  tiny  wavy  canals  called  cana- 
liculi,  connecting  one  lacuna  with  another,  and  forming  a  system 
of  minute  channels  which  communicate  with  each  other  and  with 
the  Haversian  canal.  This  constitutes  an  Haversian  System,  so 
named  from  Havers,  a  celebrated  anatomist.  Many  such  systems 
may  be  found  in  the  shaft  of  a  long  bone.  The  spaces  between 
these  systems  are  filled  by  lamellae  arranged  at  irregular  angles. 

Marrow.  —  Marrow  consists  of  fi})rous  tissue  with  blood-vessels, 
fat-cells,  marrow-cells  and  red  corpuscles.  There  are  two  distinct 
kinds  of  marrow,  yellow  and  red.  Yellow  marrow  contains  a  larger 
per  cent  of  fat,  and  is  found  in  the  medullary  canals  of  the  long 
bones.  Red  marrow  contains  less  fat,  but  is  highly  vascular  and 
occupies  the  spaces  in  cancellous  bone.  The  function  of  marrow 
is  (1)  to  support  the  blood-vessels,  lymphatics,  and  nerves;  (2)  to 
ser^•e  as  a  source  of  nourishment  for  bone ;  and  (3)  as  a  location 
for  the  formation  of  red  corpuscles.     (See  page  143.) 

Periosteum.  —  All  bones  are  covered,  except  at  the  joints,  by  a 
vascular  fibrous  membrane,  the  periosteum  (around  the  bone).  It 
consists  of  an  outer  fibrous  layer  and  an  inner  vascular  layer.  The 
attachment  of  the  periosteum  to  bone  is  rendered  firmer  by  inward 
prolongations  of  the  fibrous  layer  called  the  fibres  of  Sharpey. 

Blood-vessels.  — Unlike  cartilage,  the  bones  are  plentifully  sup- 
plied with  l)lood.  If  we  strip  the  periosteum  from  a  fresh  bone, 
we  see  many  bleeding  points  representing  the  canals  (Volkman's) 
through  which  the  blood-vessels  enter  and  where  they  leave  the 
bone.  These  blood-vessels  proceed  from  the  periosteum  to  join 
the  system  of  Haversian  canals.  Around  the  Haversian  canals  the 
lamellae  are  disposed,  while  lying  between  them,  arranged  in  circles, 
are  found  the  lacunae,  which  contain  the  bone-cells.  Running  from 
one  lacuna  to  another  in  a  radial  direction  through  the  lamellae 
towards  the  centre  are  the  canaliculi.  Following  this  scheme,  it 
will  be  seen  that  the  innermost  canaliculi  run  into  the  Haversian 
canals,  and  thus  is  established  a  direct  communication  between  the 
blood  in  these  canals  and  the  cells  in  the  lacunae  connected  with  and 
surrounding  each  Haversian  canal.     In  this  way  the  whole  sub- 


OSTCOGENETIC 
CELLS 


LAMELL/C 

LACUN/E 

CANALICUL 

HAVERSIAN 

CANAL 


COMPLETE 
AVEHSIAN 
SYSTEM 


Fig.  20.  —  Diagram  of  the  Structure  of  Osseous  Tissue.  A  small  part  of  a 
transverse  section  of  the  shaft  of  a  long  bone  is  shown.  At  the  uppermost  part 
is  the  periosteum  covering  the  outside  of  the  bone ;  at  the  lowermost  part  is  the 
endosteum  lining  the  marrow  cavity.  Between  these  is  the  compact  tissue  con- 
sisting largely  of  a  series  of  Haversian  systems,  each  being  circular  in  outline 
and  perforated  by  a  central  canal.  In  the  first  one  is  shown  only  the  area  occupied 
by  a  system ;  in  the  second  is  seen  the  concentric  arrangement  of  the  lamellae ; 
in  the  others,  respectively,  canaliculi ;  lacunae  ;  lacunae  and  canaliculi ;  the  contents 
of  the  canal,  artery,  vein,  lymphatic,  and  areolar  tissue ;  lamellae,  lacunae,  and 
canaliculi ;  and  finally  all  of  the  structures  composing  a  complete  system.  Between 
the  systems  are  circumferential  and  intermediate  lamellae,  only  a  few  of  which  are 
represented  as  lodging  lacuna>,  though  it  is  to  be  understood  that  lacunae  are  in  all 
parts.  The  periosteum  is  seen  to  be  made  up  of  a  fibrous  layer  and  a  vascular 
[ayer,  and  to  have  upon  its  attached  surface  a  stratum  of  cells.  From  the  fibrous 
layer  project  inward  the  rivet-like  fibres  of  Sharpey.      (Gerrish.) 


45 


46  ANATOMY  FOR   NURSES  [Chap.  IV 

stance  of  the  bone  is  penetrated  by  intercommunicating  channels, 
antl  the  nutrient  matters  and  mineral  salts  from  the  blood  in  the 
Haversian  canals  can  find  their  way  to  every  part. 

Function  of  periosteum  in  growth  of  bone.  —  In  the  embryo 
the  toiindation  of  the  skeleton  is  laid  in  cartilage,  or  in  primitive 
connective  tissue,  ossification  of  the  bones  occurring  later.  The 
hardening  or  ossification  of  the  bones  is  accomplished  by  the 
penetration  of  blood-vessels  and  bone-cells,  called  osteoblasts, 
from  the  periosteum.  As  they  penetrate  into  the  cartilaginous 
or  membranous  models,  they  absorb  the  cartilage  and  connective 
tissue  and  deposit  the  true  bone  tissue  at  various  points  until  they 
form  the  i)articular  bony  structure  with  which  we  are  familiar. 

Regeneration  of  bone.  —  A  fracture  is  usually  accompanied 
l)y  injur\-  to  the  periosteum  and  tissues.  This  results  in  inflam- 
mation, which  means  an  increased  amount  of  blood  is  sent  to  the 
part.  The  plasma  and  white  blood  corpuscles  from  the  blood 
exude  into  the  tissues  and  form  a  viscid  substance,  which  sticks  the 
ends  of  the  bone  together,  and  is  called  callus.  Usually  bone-cells 
from  the  periosteum  and  lime  salts  are  gradually  deposited  in  the 
callus,  which  eventually  becomes  hardened  and  forms  new  bone. 
Occasionally  the  callus  does  not  ossify  and  a  condition  known  as 
fibrous  union  results.  The  periosteum  is  largely  concerned  in  this 
process  of  repair  ;  for  if  a  portion  of  the  periosteum  be  stripped  ofl"', 
the  subjacent  bone  will  be  liable  to  die,  while  if  a  large  part  or  the 
whole  of  a  bone  be  removed,  and  the  periosteum  at  the  same  time 
left  intact,  the  bone  will  wholly  or  in  a  great  measure  be  regen- 
erated. 

SUMMARY 

CONNECTIVE  TISSUE  —  A  tissue  of  cells  with  a  great  deal  of  inter- 
ccUular  substance,  which  is  derived  from  the  cells. 

1.  Resemble  each  other  in  function. 
Reasons  for  Classification  {  2.  Resemble  each  other  in  origin. 

3.  Resemble  each  other  in  structure. 
Areolar,         Reticular, 
Fibrous,         Lymplioid, 
Elastic,         Cartilage, 
Adipose,        Bone. 
Areolar  tissue.  —  Formed  hy  interlacing  of  wavy  bundles  of  white  fibres 

and  some  straight  elastic  fil)res  with  cells  lying  in  the  spaces. 
Fibrous  tissue.  —  Formed  of  wavy  bundles  of  white  fibres  only,  with  cells 
in  rows  between  bundles.     \'ery  strong  and  tough  but  pUant. 


Classification 


Chap.  IV] 


CONNECTIVE  TISSUES 


47 


Function  - 


Elastic  tissue.  —  Formed  of  yellow  elastic  fibres  with  few  bundles  of  white 
fibres.     It  is  extensile  and  elastic. 

■  Areolar  tissue  connects,  insulates,  forms  protecting  sheaths,  and 

is  continuous  throughout  the  whole  body. 
Fibrous  tissue  is  found  in  form  of   ligaments,  tendons,  apo- 
neuroses, protecting  sheaths,  and  fasciae. 
Elastic  tissue  serves  same  purpose  as  India  rubber.     Saves 
wear  and  tear  of  muscles.     Found  in  ligamenta  flava,  blood- 
vessels, air-tubes,  vocal  cords,  lungs,  and  larynx. 
Adipose  tissue.  — ■  Modification  of  areolar  tissue,  with  cells  enlarged  and 
filled  with  fat.     Distribution  quite  general  but  not  uniform. 

1.  Confers  graceful  outlines. 

2.  Forms  a  reserve  fund  for  the  production  of  heat  and  energy. 

3.  Prevents  the  too  rapid  loss  of  heat. 
.4.  Serves  to  protect  and  support  delicate  organs. 

Reticular  tissue.  — ■  Network  of  white  fibres  with  few  yellow  fibres.  Cells 
wrapped  around  fibres. 

Lymphoid  tisstie.  —  Reticular  tissue  with  meshes  of  network  occupied  by 
Ijaiiph  corpuscles. 

Function.  —  Lymphoid  tissue  forms  the  structure  of  the  spleen  and  lymph- 
nodes.     Also  enters  into  composition  of  glands  and  mucous  membranes. 

Cartilage.  —  Cartilage  or  gristle  is  a  bluish  white  tissue,  firm  and  elastic, 

covered  and  nourished  by  perichondrium. 

,,     ,.  .,  Articular 

Hyaline  cartilage 


Function 


Varieties  • 


Skeletal. 


Costal 

2.  White  fibro-caitilage. 

3.  Yellow  fibro-cartilage. 

Hyaline  —  Small  number  of  cells  in  an  abundant  quantity  of  intercellular 
substance.  Found  as  articular  cartilage,  covering  ends  of  bones  in 
joints.  Found  as  costal  cartilage,  connecting  ribs  and  sternum,  or  one 
rib  with  another. 
White  Fi6ro  — Intercellular  substance  pervaded  with  white  fibres.  Re- 
sembles fibrous  tissue.  Found  between  spinal  and  pubic  bones. 
Yellow  Fibro  —  Intercellular  substance  pervaded  with  network  of  yellow 
elastic  fibres.     Found  in  parts  of  throat  and  ear. 

Serves  as  cushions  for  ends  of  bones. 
Makes  a  flexible  connection  between 
the  ribs  and  the  sternum,  or  be- 
tween one  rib  and  another. 
Strengthens  and  maintains  shape 
of  certain  organs  without  rigidity. 

(Serves  as  strong,  flexible  connecting 
material  between  bones,  and  around 
some  joints. 
(Strengthens  and  maintains  shape  of 
certain  organs,  and  yet  allows  of 
certain  amount  of  elasticity. 


Hyaline  Cartilage 


Function 


48 


ANATOMY  FOR   NURSES 


[Chap.  IV 


& 

o 

M 
CO 
CO 

O 

Qi 
O 

CO 
M 

O 

n 


Composition 


Varieties 


Canals 


Haversian 

System 


I  Haversian 


(Calcium  phosphate. 
Calcium  carbonate. 
Small  portion  of  other  salts. 
i  Blood-vessels. 
Connective  tissue. 
Marrow. 
Cancellated  or  .spongy. 
Dense  or  compact  like  ivory. 
[  Medullary  —  Yellow  Marrow. 
I  Blood-vessels. 
I  Lymphatics. 
Haversian  canal. 
Lamellae  —  bony  fibres  arranged  in  rings  around 

Haversian  canal. 
Lacunae  —  small  spaces  between  lamellae  occupied 

b,v  bone  cells. 
Canaliculi  —  canals  which  radiate  from  lacunae  to 
the  Haversian  canal. 
Endosteum  —  A  fibrous  membrane  that  lines  the  medullary  canal. 
Fibrous  tissue,  blood-vessels,  fat-cells,  mar- 
row cells,  and  red  corpuscles. 
(Yellow  —  found  in  medullary  canals  of  long 
bones. 
Red  —  occupies  spaces  in  cancellous  bone. 

1.  Supports  blood-vessels,  Ijmaphatics,  and 
nerves. 

2.  Serves  as  a  source  of  nourishment  for 
bone. 

3.  Serves  as  location  for  formation  of  red 
corpuscles. 

Periosteum  —  A  vascular  fibrous  membrane  that  covers  the  bones 
and  serves  to  nourish  them.     Important  in  reunion  of  broken  bone 
and  growth  of  new  bone. 
(  Fibres  of  Sharpey  —  Inward  prolongations  of  periosteum. 


Marrow 


Consists  of 


Varieties 


Fimction 


CHAPTER  V 

THE    SKELETON 

Function.  —  The  bones  are  the  principal  organs  of  support,  and 
the  passive  instruments  of  locomotion.  Connected  together  in  the 
skeleton,  they  form  a  framework  of  hard  material,  affording  at- 
tachment to  the  soft  parts,  maintaining  them  in  their  due  posi- 
tion, sheltering  such  as  are  of  delicate  structure,  giving  stability 
to  the  whole  fabric,  and  preserving  its  shape. 

The  entire  skeleton  in  the  adult  consists  of  two  hundred  and  six 
named  bones.     These  are  :  — 

Cranium 8 

Face 14 

f  Malleus  2 

Ear     Incus  2  6 

[  Stapes  2 

Hyoid 1 

The  spine,  or  vertebral  column 
(sacrum  and  coccyx  included)       26 

Sternum  and  ribs 25 

Upper  extremities 64 

Lower  extremities 62 

206 
In  this  enumeration  the  sesamoid^  bones,  which  are  found  em- 
bedded in  tendons  covering  the  bones  of  the  knee,  hand,  and  foot, 
are  not  included. 

CLASSIFICATION 

The  bones  may  be  divided,  according  to  their  shape,  into  four 
classes:  1.  Long,     2.  Short,     3.  Flat,     and  4.  Irregular. 

Long  bones.  —  A  long  bone  consists  of  a  shaft,  and  two  extrem- 
ities. The  shaft  is  formed  mainly  of  compact  tissue,  this  compact 
tissue  being  thickest  in  the  middle,  where  the  bone  is  most  slender 

1  Ses'amoid  [from  the  Greek  sesamon,  a  "seed  of  the  sesamum  "  and  eidos,  "form," 
"resemblance"],  resembling  a  grain  of  sesamum. 
E  49 


50 


ANATOMY  FOR  NURSES 


[Chap.  V 


and  the  strain  greatest,  and  it  is  hollowed  out  in  the  interior  to 
form  the  medullary  canal.  The  extremities  are  made  up  of  can- 
cellated tissue  with  only  a  thin  coating  of  compact  substance,  and 


.  PARIETAL 
-TEMPO  RA  I. 


CARPUS 
METACARPUS 


Fig.  21.  —  The  Human  Skeleton.     (Morrow.) 


are  more  or  less  expanded  for  greater  convenience  of  mutual  con- 
nection, and  to  afford  a  broad  surface  for  muscular  attachment. 
All  long  bones  are  more  or  less  curved,  which  gives  them  greater 
strength  and  a  more  graceful  outline. 
The  long  bones  are  as  follows :  — 


Chap.  Y]  THE  SKELETON  51 

2  Clavicle  2  Tibia 

2  Humerus  2  Fibula 

2  Radius  10  Metacarpals 

2  Ulna  10  Metatarsals 

2  Femur  56  Phalanges 

90 
Short  bones.  —  The  short  bones  are  small  pieces  of  bone  ir- 
regularly shaped.  Their  texture  is  spongy  throughout,  excepting 
at  their  surface,  where  there  is  a  thin  crust  of  compact  substance. 
The  short  bones  are  the  sixteen  bones  of  the  carpus,  and  the  four- 
teen bones  of  the  tarsus.  Some  authors  include  the  two  patellae. 
Flat  bones.  —  Where  the  principal  requirement  is  either  exten- 
sive protection  or  the  provision  of  broad  surfaces  for  muscular 
attachment,  the  bony  tissue  expands  into  broad  or  elongated 
flat  plates  which  are  composed  of  two  thin  layers  of  compact 
tissue,  enclosing  between  them  a  variable  quantity  of  cancellous 
tissue. 

The  flat  bones  are  as  follows  :  — 

1  Occipital  2  Lacrimal 

2  Parietal  2  Scapula 

1  Frontal  1  Sternum 

2  Nasal  24  Ribs 

1  Vomer  2  Hip  bones 

38 
Irregular  bones.  —  The  irregular  bones  are  those  which,  ok 
account  of  their  peculiar  shape,  cannot  be  grouped  under  either 
of  the  preceding  heads. 

The  irregular  bones  are  as  follows  :  — 

24  Vertebrae  2  ]\Ialar 

1  Sacrum  2  Maxillse 

1  Coccyx  1  Mandible 

2  Temporal  2  Palate 

1  Sphenoid  2  Inferior  turbinated 

1  Ethmoid  J.  Hyoid 

40 
The  bones  of  the  ear  are  so  small  that  they  are  described  as  ossicles 
and  do  not  fit  in  any  of  these  groups. 

Processes  and  Depressions.  —  If  the  surface  of  any  bone  is 
examined,  certain  projections  and  depressions  are  seen.     The  pro- 


52  ANATOMY   FOR   NURSES  [Chap.  V 

jections  are  called  processes.  The  depressions  are  called  fossae 
or  cavities,  and  either  a  qualifying  adjective  is  used  to  describe 
them,  or  a  special  name  given  to  them.  Processes  and  depressions 
are  classified  as  :  1.  Articular,  2.  Non-articular.  The  articular  are 
provided  for  the  mutual  connection  of  bones  to  form  joints.  The 
non-articular  serve  for  the  attachment  of  ligaments  and  muscles. 
The  following  terms  are  used :  — 

Prucc.ss.  —  Any  marked  bony  prominence. 

Tuberosity.  —  A  large  process. 

Tubercle.  —  A  small  process. 

Syinous.  —  A  sharp,  slender  process. 

Cre^t.  —  A  narrow  ridge  of  bone. 

Condyle.  —  A  rounded  or  knuckle-like  process. 

Head.  —  A  portion  supported  on  a  constricted  part  or  neck. 

Fossa.  —  A  depression  in  or  upon  a  bone. 

Cavities.  —  The  terms  sinus '  and  antrum  are  applied  to  cavities 
within  certain  bones. 

Meatus  or  Canal.  —  A  long  tube-like  passageway. 

Fissure.  —  A  narrow  slit. 

Foramen.  —  A  hole  or  orifice  through  which  blood-vessels, 
nerves,  and  ligaments  arc  transmitted. 

DIVISIONS  OF  THE  SI^LETON 

In  taking  up  the  various  divisions  of  the  skeleton,  we  will 
consider  it  as  consistins:  of  — 


1.  Head  or  skull 

2.  Ilyoid. 

3.  Trunk     .     . 


Cranium. 
Face. 

Vertebrae. 
Sternum. 
I  Ribs. 

4.  Upper  extremities. 

5.  Ix)wer  extremities. 

The  head  or  skull.  —  The  head  or  skull  rests  upon  the  spinal 
column,  and  is  formed  by  the  union  of  the  cranial  and  facial 
bones.  It  is  divisible  into — 1.  Cranium  or  brain  case,  and 
2.  Anterior  region,  or  face. 

'  The  term  "sinus  "  is  also  used  in  surgeiy  to  denote  a  narrow  tract  leading  from 
the  surface  down  to  a  cavity. 


Chap.  V] 


THE  SKELETON 


53 


BONES   OF  THE   CRANIUM 

Occipital 1 

Parietal 2 

Frontal       1 

Temporal 2 

Ethmoid 1 

Sphenoid 1 

Occipital  bone.  —  It  is  situated  at  the  back  and  base  of  the 
skull.     At  birth  the  bone  consists  of  four  parts,  which  do  not 

vertex 


Sinciput 


Occiput 


Fig.  22.  —  Side  View  of  the  Skull.     (Morrow.) 

Attention  of  the  student  is  called  to  the  text,  page  64,  where  the  word  Mandible 
is  used  in  preference  to  the  term  Inferior  Maxillary  which  is  found  on  the  illustra- 
tion.    The  word  Maxilla  is  also  used  in  preference  to  Superior  Maxillary. 

unite  into  a  single  bone  until  the  sixth  year.  The  internal  sur- 
face is  deeply  concave,  and  presents  many  eminences  and  depres- 
sions for  the  reception  of  parts  of  the  brain.  There  is  a  large 
hole  —  the  foramen  magnum  —  in  the  inferior  portion  of  the 
bone,  for  the  transmission  of  the  medulla  oblongata  (the  con- 
stricted portion  of  the  brain)  where  it  narrows  down  to  join  the 
spinal  cord.     At  the  sides  of  the  foramen  magnum  it  presents 


54 


ANATOMY   FOR  NURSES 


[Chap.  V 


two   processes   called   condyles,   which   articulate   with  the   first 
vertebra. 

Parietal  bones.  —  The  right  and  left  form  by  their  union  the 
greater  part  of  the  sides  and  roof  of  the  skull.  The  external  sur- 
face is  convex  and  smooth  ;   the  internal  surface  is  concave,  and 


Ftg.  23.  —  Front  View  of  the  Skull.     (Morrow.) 

See  note  under  Figure  22  regarding  use  of  Mandible  and  Maxilla  in  pr«ferer.ce 
to  Inferior  Maxillary  and  Superior  Maxillary.  Note  also  that  the  spelling  o^  the 
word  Lachrymal  differs  from  the  more  correct  spelling  found  in  the  text,  as  per  the 
B.  x\.  A. 

presents  eminences  and  depressions  for  lodging  the  convolutions  of 
the  brain,  and  numerous  furrows  for  the  ramifications  of  arteries 
which  supply  the  dura  mater  (membrane  which  covers  the  brain) 
with  blood. 

Frontal  bone.  —  It  resembles  a  cockle  shell,  and  not  only  forms 
the  forehead,  but  also  enters  into  the  formation  of  the  roof  of  the 
orbits,  and  of  the  nasal  cavity.  The  arch  formed  by  part  of  the 
frontal  bone  over  the  eye  is  sharp  and  prominent,  and  is  known  as 


Chap.  V] 


THE  SKELETON 


the  supraorbital  margin.  Just  above  the  supraorbital  margins  are 
hollow  spaces  called  the  frontal  sinuses  (see  Fig.  33)  which  are 
filled  with  air  and  open  into  the  nose.  In  the  upper  and  outer 
angle  of  each  orbit  are  two  depressions  called  lacrimal  fossae  for 
the  reception  of  the  glands  of  the  same  name,  which  secrete  the 
tears.  At  birth  the  bone  consists  of  two  pieces,  which  afterwards 
become  united  along  the  middle  line,  by  a  suture  ^  which  runs  from 


Fig.  24.  —  Occipital  Bone.     Inner  surface. 

the  vertex  of  the  bone  to  the  root  of  the  nose.  This  suture  usually 
becomes  obliterated  within  a  few  years  after  birth,  but  it  occasion- 
ally remains  throughout  life. 

Temporal  bones.  —  The  right  and  left  are  situated  at  the  sides 
and  base  of  the  skull.  They  are  named  temporal  from  the  Latin 
word  tempus,  time,  as  it  is  on  the  temple  the  hair  first  becomes 
gray  and  thin,  and  thus  shows  the  ravages  of  time.  The  temporal 
bones  are  divided  into  three  parts  —  the  hard,  dense  portion, 
called  petrous;  a  thin  and  expanded  scale-like  portion,  called 
squamous;    and  a  mastoid  portion,  which  is  prolonged  down- 

1  See  Figs.  61  and  62. 


56 


ANATOMY  FOR  NURSES 


[Chap.  V 


"^^ 


Fig.  25. 


Pariet.\l  Bone.     Inner  surface.     ^4,  parietal  depression;    E,  fur- 
row for  ramification  of  arteries. 


ward  and  forms  the  mastoid  process.  This  process  is  filled  with 
a  number  of  connected  cancellous  .spaces,  containing  air,  and 
called  mastoid  cells.'  They  communicate  with  the  cavity  of 
the  middle  ear.  The  condition  known  as  mastoiditis  means  in- 
flammation of  the  lininj:  of  these  cells. 


Supraorbital 
Margin 
Roof  of 
Orbital  Cavity 


'  Cells.  —  The  student  must  bear  in  mind  that  the  word  cell  is  used  with  two 

different  meanings  in  anatomy.     Histologically  speaking,  the  word  "cell"  refers  to 

one  of  the  component  units  of  the  body,  such  as  an  "epithelial  cell"  or  "nerve  cell." 

In  connection  with  the  use  of  the  words  "mastoid  cells"  in  the  text,  the  word 

"cells"  refers  to  tiny  enclosed  hollow  chambers  similar  to  the  cells  of  a  honey-comb. 


Chap.  V] 


THE   SKELETON 


57 


The  internal  ear,  the  essential  part  of  the  organ  of  hearing, 
is  contained  in  a  series  of  cavities,  channelled  out  of  the  substance 
of  the  petrous  portion.     Between  the  squamous  and  petrous  por- 


DIGASTRIC 
FOSSA 


Fig.  27.  —  The  Right  Temporal  Bone.  Outer  surface.  The  dotted  lines 
indicate  the  lines  of  suture  between  squamous,  mastoid,  and  petrous  portions. 
(Gerrish.) 

tions  is  a  socket,  called  the  glenoid  fossa,  for  the  reception  of  the 
condyle  of  the  lower  jaw. 

Ethmoid  bone. — -It  is  an  exceedingly  light  cancellous  bone 
that  forms  part  of  the  orbits,  nasal  fossae,  and  base  of  the  cranium. 
It  consists  of  a  horizontal  plate,  a  verti- 
cal plate,  and  two  lateral  masses.  The 
horizontal  plate  forms  the  roof  of  the 
nasal  fossae,  and  also  closes  the  anterior 
part  of  the  base  of  the  cranium.  It  is 
pierced  by  numerous  foramina  or  holes, 
through  which  the  nerves  conveying  the 
sense  of  smell  pass.  Descending  from 
the  horizontal  plate  is  the  vertical  plate 
which  helps  to  form  the  nasal  septum, 
and  on  either  side  the  lateral  masses 
help  to  form  the  side  walls  of  the  nasal 

fossse.       The    lateral    masses    contain    a  Fig.  28.  -  Ethmoid  Bone. 

Seen  fromunder  surface.  2,criD- 
number    of    thin-walled    cavities    called      riform  or  perforated  plate. 


58 


ANATOMY  FOR   NURSES 


[Chap.  V 


T  ZoM^UA^. 


the  ethmoidal  sinuses,  wliich  communicate  with  the  nasal  fossae. 

Descending  from  the  horizontal  plate  on  either  side  of  the  septum 

are  two  processes  of 
very  thin,  cancellous, 
bony  tissue,  named  the 
superior  and  middle  tur- 
binated processes. 

Sphenoid  bone.  —  It 
is  situated  at  the  an- 
terior part  of  the  base  of 
the  skull  and  binds  the 
other  cranial  bones  to- 
gether. It  helps  to  form 
tlie  cavities  of  the  cra- 
nium, orbits,  and  nasal 
fossae.  In  form  it  some- 
what resembles  a  bat 
^    „„      ^  with    extended    wings, 

Fig.  29.  —  Parietal,    Temporal,    and    Sphe-  .                -i     j 

NOiD  Bones.     Posterior  aspect.     1,  body  of  sphe-  and  IS  described  aS  COn- 

noid  bone;    2,  2,  preater  wings  of  sphenoid  bone;  •  j.'    „    _f    _    U^J,,     +,,r„ 

3,  3,  parietal  bones ;   4,  4,  mastoid  process  of  tem-  ^^^l^mg    01    a    DOQJ  ,    tWO 

poral  bones.     (Gould's  Dictionary.)  pairs       of       wiugS,       and 

two  pterygoid  processes. 
The  body  is  joined  to  the  ethmoid  in  front  and  the  occipital  be- 
hind. It  contains  cavities  which  are  called  sphenoidal  sinuses. 
They  communicate  with  the  nasal  fossae. 

THE  SKULL  AS  A  WHOLE 

The  cranium  is  a  firm  case  or  covering  for  the  brain.  Four  of  the 
eight  bones  which  form  this  bony  covering  are  classed  as  flat 
bones.  They  consist  of  two  layers  of  compact  tissue,  the  outer 
one  thick  and  tough,  the  inner  one  thinner  and  more  brittle.  The 
cancellated  tissue  lying  between  these  two  layers,  or  "  tables  of  the 
skull,"  is  called  the  diploe.  The  base  of  the  skull  is  much  thicker 
and  .stronger  than  the  walls  and  roof;  it  presents  a  number  of 
openings  for  the  passage  of  the  cranial  nerves,  blood-vessels,  etc. 

The  bones  of  the  cranium  begin  to  develop  at  a  very  early 
period  of  fcetal  life.  Thus,  before  birth  the  bones  at  the  top  and 
sides  of  the  skull  are  separated  from  each  other  by  membranous 
tissue  in  which  bone  is  not  yet  formed,  and  being  then  imperfectly 


Chap.  V] 


THE  SKELETON 


59 


Fig.  30.  —  Skull  of  Xew-born  Child. 
To  show  moulding.     (Edgar.) 


ossified,  they  are  readily  moulded,  and  they  overlap  one  another 
more  or  less  during  parturition.  The  spaces  at  the  angles  of  the 
bone  occupied  by  the  membra- 
nous tissue  are  termed  the  fon- 
tanelles,  so  named  from  the 
pulsations  of  the  brain,  which 
can  be  seen  in  some  of  them  and 
which  the  early  anatomists  lik- 
ened to  the  rise  and  fall  of  water 
in  a  fountain.  There  are  six  of 
these  fontanelles. 

Anterior  Fontanelle.  —  The 
anterior  fontanelle  is  the  larg- 
est, and  is  a  lozenge-shaped 
space  between  the  angles  of  the 
two  parietal  bones  and  the  two  segments  of  the  frontal  bone.  It 
remains  open  until  the  second  year,  and  occasionally  persists 
throughout  life. 

Posterior  Fontanelle.  —  The  posterior  fontanelle  is  much  smaller 
in  size,  and  is  a  triangular  space  between  the  occipital  and  two 
parietal  bones.     This  is  closed  by  an  extension  of  the  ossifying 

process  a  few  months  after  birth. 
(See  Figs.  61  and  62.) 

The  other  four  fontanelles,  two 
on  each  side  of  the  skull,  are 
placed  at  the  inferior  angles  of 
the  parietal  bones ;  they  are  un- 
important. Small,  irregular  os- 
sicles called  sutural  bones  (Wor- 
mian bones)  are  found  in  the 
sutures  of  the  head,  chiefly  near 
the  fontanelles,  and  often  assist 
in  the  closure  of  the  fontanelles. 
Sinuses  of  the  head.  —  Four 
sinuses  communicate  with  each 
nasal  cavity  :  the  frontal,  ethmoid,  sphenoid,  and  maxillary  or  an- 
trum of  Highmore.  The  mucous  membrane  which  lines  the  nose 
also  lines  all  of  these  sinuses,  and  inflammation  of  this  membrane 
may  extend  into  any  of  them  and  cause  sinusitis.     (See  Fig.  90.) 


Fig.  31.  —  Skull  of  New-born  Child 
To  show  moulding.      (Edgar.) 


60 


ANATOMY  FOR  NURSES 


[Chap.  V 


BONES   OF  THE   FACE 

Nasal 2 

Vomer 1 

Inf.  Turbinated 2 

Lacrimal 2 

Malar 2 

Palate 2 

Maxillffi 2 

ISIandible 1 

14 

Nasal  bones.  —  They  are  two  small  oblong  bones 
placed  side  by  side  at  the  middle  and  upper  part  of 
the  face,  forming  by  their  junction  "  the  bridge  "  of 
the  nose. 

Vomer.  —  It  is  a  single  bone  placed  at  the  lower 
and  back  part  of  the  nasal  cavity,  ami  forms  part  of 
the  central  septum  of  the  nasal  fossae.  It  is  thin, 
and  shaped  somewhat  like  a  ploughshare,  but  varies 
in  different  individuals,  being  frequently  bent  to  one 
or  the  other  side,  thus  making  the  nasal  chambers 
of  unequal  size. 

Inferior  turbinated  bones.  —  Thcv  are  situated  in  the  nostril. 


Fig.  32.  — 
Nasal  Bones. 
Viewed  from 
before.  (Ger- 
rish.) 


ANTER 
TINE    GROOVE 


HARD    PALATE 


Fig.  33. 


-  Sagittal  Section  of  Face,  a  Little  to  the  Left  of  the  Middle 
Line,  showing  the  Vomer  and  its  Relations.     (Gerrish.) 


Chap.  V] 


THE   SKELETON 


61 


LACRIMAL 
PROCESS 


ETHMOID 
PROCESS 


Fig.  34.  —  Right  Inferior  Turbinate 
Bone.     External  surface.     (Gerrish.) 


on  the  outer  wall  of  each  side.  Each  consists  of  a  layer  of  thin, 
cancellous  bone,  curled  upon  itself  like  a  scroll ;  hence  its  name, 
"turbinated."  They  are  below  the  superior  and  middle  turbi- 
nated processes  of  the  ethmoid 
bone.  Abnormal  conditions  of 
these  bones  and  the  membranes 
covering  them  cause  some  of  the 
more  common  nasal  diseases. 
(See  Fig.  140.) 

Lacrimal  bones.  —  Are  the 
smallest  and  most  fragile  bones  of 
the  face.  They  are  situated  at  the  front  part  of  the  inner  wall 
of  the  orbit,  and  resemble  somewhat  in  form,  thinness,  and  size, 
a  finger-nail.  They  are  named  lacrimal  because  they  contain  part 
of  the  canal  through  which  the  tear  duct  runs. 

Malar,  or  yoke  bone. — Forms  the  prominence  of  the 
cheek,  and  part  of  the  outer  wall  and  floor  of  the  orbit. 
A  prominent  spine  of  bone  projects  backward  from 
the  body  of  the  malar,  and  articulates  by  its  free 
extremity  with  the  corresponding  spine  projecting 
forward  from  the  temporal  bone,  thus  making  the 
two  members  of  the  true  arch  known  as  the  zygo- 
matic arch. 

Palate  bones.  —  They  are  shaped  like  an  "  L," 
and  form  (1)  the  back  part  of  the  roof  of  the  mouth ;  (2)  part 
of  the  floor  and  outer  wall  of  the  nasal  fossae;  (3)  a  very 
small  portion  of  the  floor  of  the  orbit. 


Fig.  35.  — 
Lacrimal 
Bone. 


FRONTAL   PROCESS 


ZYGOMATIC 
PROCESS-"" 


MhXILLARV 
PROCESS 


Fig.  36.  —  Right  Malar  Bone.     Outer  surface.     (Gerrish.) 


62 


ANATOMY   FOR   NURSES 


[Chap.  V 


Maxillae,  or  upper  jaw-bones,  also  known  as  superior  maxillary. 
—  The  maxilhv  are  two  in  number  (right  and  left)  and  are  the  prin- 


gXTAL  PRoc, 


PTERYGOID   FOSSA 


Fig.  37. 


The  Two  Pal.\te  Bones  in  their  N.\tuu.\l  Position.     Dorsal  view. 
(Gcrrish.) 


cipal  bones  of  the  face.  Each  bone  assists  in  forming  (1)  part 
of  the  floor  of  the  orbit,  (2)  the  floor  and  outer  wall  of  the  nasal 
fossa?,  (3)  the  greater  })art  of  the  roof  of  the  mouth.  These 
bones  usually  unite  before  birth  to  form  one  bone.  When  they 
fail  to  do  so  we  have  the  condition  known  as  cleft  palate.     From 


NA3AL 
ROCCSS 


POSTERIOR    OEN-  '. 
T«L   CANALS         i 


FRAORBITAL 
FO  R  A  M  E  N 
ASAL    NOTCH 

TERIOR    NASAL 
SPINE 


Fig.  38.  —  The  Right  Ma.xilla.     Outer  surface.     (Gerrish.) 

a  surgical  point  of  view,  it  is  the  most  important  bone  of  the  face, 
on  account  of  the  number  of  diseases  to  which  it  is  liable. 

That  part  of  the  bone  which  contains  the  teeth  is  called  the  al- 


Chap.  V] 


THE  SKELETON 


63 


veolar  process,  and  is  excavated  into  cavities,  varying  in  depth 
and  size  according  to  the  size  of  the  teeth  they  contain.  The 
body  of  the  bone  is  hollowed  out  into  a  large  cavity  known  as  the 
antrum  of  Highmore,  which  opens  into  the  nose.  Abnormal 
conditions  of  either  the  nose  or  teeth  may  cause  an  infection  of 
these  antrums. 

Mandible,  or  lower  jaw-bone,  also  known  as  inferior  maxillary. 
—  It  is  the  largest  and  strongest  bone  of  the  face.     At  birth,  it 


ENTAL 
PROTUBERANCE 


Fig.  39.  —  The  Mandible. 


Viewed  from  the  right  and  a  little  in  front. 
(Gerrish.) 


consists  of  two  lateral  halves,  which  join  and  form  one  bone  during 
the  first  or  second  year.  It  serves  for  the  reception  of  the  lower 
teeth,  and  undergoes  several  changes  in  shape  during  life,  owing 
mainly  (1)  to  the  first  and  second  dentition,  (2)  to  the  loss  of 
teeth  in  the  aged,  and  (3)  the  subsequent  absorption  of  that  part 
of  the  bone  which  contained 
them.  It  articulates,  by 
its  condyles,  with  the  sock- 
ets in  the  temporal  bones, 
which  allows  for  free  move- 
ment in  mastication. 

Hyoid  bone  (os  hyoi- 
deum).  —  Is  an  isolated  U- 
shaped  bone  lying  in  front 
of  the  throat,  just  above  the  laryngeal  prominence  (Adam's 
apple).  It  supports  the  tongue,  and  gives  attachment  to  some 
of  its  numerous  muscles. 


Fig.  40.  ^-  The   Hyoid   Bone.     Viewed   from 
the  left  and  in  front.     (Gerrish.) 


64 


ANATOMY   FOR  NURSES 


[Chap.  V 


TRUNK 

The  hoiu's  which  enter  into  tlie  formation  of  the  trunk  consist 
of  the  vertebrae,  sternum,  and  ribs. 

The  vertebral  column  as  a  whole.  —  It  is  formed  of  a  series  of 
bones  called  vertebra^,  and  in  a  man  of  average  height  is  about 


CERVICAL 
VERTEBRJC 


b 


K 


THORACIC 
VERTEBRiC 


LUMBAR 
VERTEBRA 


Fig.   41.  —  The  Vertebral  Column.     Right  lateral  view  and  dorsal  view. 

(Gerrish.) 


twenty-eight  inches  long.  In  youth  the  vertebrae  are  thirty-three 
in  number,  and  according  to  the  position  they  occupy  are 
named :  — 


Chap.  V]  THE  SKELETON  65 

Cervical,  in  the  neck 7 

Thoracic,  in  the  thorax 12 

Lumbar,  in  the  loins 5 

Sacral,  in  the  pelvis 5 

Coccygeal,  in  the  pelvis      .....  4 

The  vertebrae  in  the  three  upper  portions  of  the  spine  are 
separate  and  movable  throughout  the  whole  of  life,  and  are  known 
as  true  vertebrse.  Those  found  in  the  sacral  and  coccygeal  re- 
gions are,  in  the  adult,  firmly  united,  so  as  to  form  two  bones,  five 
entering  into  the  upper  bone,  or  sacrum,  and  four  into  the  ter- 
minal bone  of  the  spine,  or  coccyx.  They  are  known  as  false 
vertebrae,  and  on  account  of  their  union  the  number  of  vertebrae 
in  the  adult  is  twenty-six.  The  bodies  of  the  vertebrae  are  piled 
one  upon  another,  forming  a  strong,  solid  pillar,  for  the  support 
of  the  cranium  and  trunk,  the  arches  forming  a  hollow  cylinder 
behind  for  the  protection  of  the  spinal  cord.  Viewed  from  the 
side,  it  presents  four  curves  which  are  alternately  convex  and 
concave.  The  two  concave  ones  are  called  primary  curves  because 
they  exist  in  foetal  life 

and  are  designed  for  spinous  rrocr.,    i'"^^CC' 

the     accommodation  1\*^^~   ^  *' 

of  viscera.    The  other  L^^  "'  m 

two  are  called  second- 
ary or  compensatory 
curves  because  they        AHicuiar./        ^ 

Process    ~         ))!»  miiir 

enable  the  child  to  as-  \  m 

sume  the  erect  atti-    Trausverse^:^/  ^im\\<i '^^.^^m 

1  Process , 

tude. 

The     vertebrae.  — 

Each    vertebra    con-       ^o'* 

sists  of  two   essential  Fig.  42.  —  A  Ckrvical  Vertebua. 

parts,     an     anterior 

solid  portion  or  body,  and  a  posterior  portion  or  arch.  Each 
arch  has  seven  processes  :  four  articular,  two  to  connect  with  bone 
above,  two  for  bone  below ;  two  transverse,  one  at  each  side,  and 
one  spinous  process,  projecting  backward. 

Cervical  vertehros.  —  In  the  cervical  region  of  the  vertebral  col- 
umn the  bodies  of  the  vertebrae  are  smaller  than  in  the  thoracic, 
but  the  arches  are  larger.     The  spinous  processes  are  short,  and 

F 


66 


ANATOMY  FOR   NURSES 


[Chap.  V 


COSTO-TRANS- 
VERSE  FORAMEN 


TRANSVERSE/.»- 
PROCESS. 


Fig.  43.  —  The  Atl.\8.     Viewed  from  above.      (Gerrish.) 

are  often  cleft  in  two,  or  bifid.  The  transverse  processes  are 
pierced  by  a  foramen  for  the  passage  of  blood  vessels  and  nerves. 
The  first  and  second  cervical  vertebrae  differ  considerably  from 
the  rest.  The  first,  or  atlas,  so  named  from  supporting  the  head, 
has  practically  no  body,  and  may  be  described  as  a  bony  ring 
divided  into  two  sections  by  a  transverse  ligament.  The  dorsal 
section  of  this  ring  contains  the  spinal  cord,  and  the  ventral  or 
front  section  contains  the  bony  projection  which  arises  from  the 
upper  surface  of  the  body  of  the  second  cervical  vertebra,  axis 
(epistropheus).  This  bony  projection,  called  the  odontoid  process, 
forms  a  pivot,  imd  around  this  pivot  the  atlas  rotates  when  the  head 

is  turned  from  side  to 
side,  carrying  the 
skull,  to  which  it 
is  firmly  articulated, 
with  it. 

Thoracic     vertebrae. 


ODONTOID    PROCESS. 


ARTICULAR    FACET 

FOR    VENTRAL 
ARCH    OF    ATLAS. 


SPINOUS    PROCESS 


TRANSVERSE 
PROCESS. 


Fig.  44.  —  The  Axis  (Epi.stkopheus). 
side.     (Gerrish.) 


Its  right 


—  The  bodies  of  the 
thoracic  vertebrae  are 
larger  and  stronger 
than  those  of  the 
cervical ;  and  have  a  facet  or  demi-facet  for  articulation  with  the 
vertebral  end  of  a  rib. 

Lumbar  vertebra'.  —  The  bodies  of  the  lumbar  vertebrae  are  the 
largest  and  heaviest  in  the  whole  spine. 

Structure  of  vertebral  column.  —  The  different  vertebrae  are 
connected  together  (1)  by  means  of  the  articular  processes,  (2)  by 
disks  of  intervertebral  fibro-cartilage  placed  between  the  vertebral 
bodies,  and  (3)   by  broad   thin  ligaments  called  the   ligamenta 


Chap.  V] 


THE  SKELETON 


67 


flava  which  connect  the  transverse  processes.  The  spinal  curves 
confer  a  considerable  amount  of  springiness  and  strength  upon  the 
spinal  column,  which  would  be  lacking  were  it  straight,  and  the 
elasticity  is  further  increased  by  the  ligamenta  flava,  and  the  disks 
of  fibro-cartilage.  These  disks  or  pads  also  mitigate  the  effects 
of  concussion  arising  from  falls  or  blows,  and  allow  of  a  certain 
amount  of  motion  between  the  vertebrae.  The  amount  of  motion 
permitted  is  greatest  in  the  cervical  region. 

Abnormal  conditions.  —  As  a  result  of  injury  or  disease  the 
normal  curves  may  become  exaggerated  and  are  then  spoken  of  as 
curvatures.     Curvatures  may  be  lateral,  dorsal,  or  ventral. 


FALSE    RIBS 


FLOATING   RIBS 


J.  J.IESNABD. 


Fig.  45.  —  Thorax.     (10th  rib  is  defective ;  it  should  be  attached  to  the  costal 

cartilage  above.). 


68 


ANATOMY  FOR  NURSES 


[Chap.  V 


It  occasionally  happens  that  the  arch  of  one  of  the  vertebrae 
does  not  develop  properly,  and  as  a  result  the  membranes  and 
fluid  of  the  spinal  cord  will  protrude,  forming  a  tumor  upon  the 
child's  back.     This  condition  is  called  spina  bifida. 

Sacrum  (os  sacrum).  —  The  sacrum  is  formed  by  the  union 
of  the  five  sacral  vertebrae.  It  is  a  large  triangular  bone  situated 
like  a  wedge  between  the  coxal  bones,  and  is  curved  upon  itself 
in  such  a  way  as  to  give  increased  capacity  to  the  pelvic  cavity. 

Coccyx  (os  coccygis). 
—  The  coccj'x  is  usually 
formed  of  four  small  seg- 
ments of  bone,  and  is  the 
most  rudimentary  part 
of  the  vertebral  column. 

THORAX 

The  thorax  is  an  elon- 
gated bony  cage  formed 
by  the  sternum  and  cos- 
tal cartilages  in  front, 
the  twelve  ribs  on  each 
side,  and  the  bodies  of 
the  twelve  thoracic  ver- 
tebrae behind.  It  con- 
tains and  protects  the 
principal  organs  of  res- 
piration and  circulation. 

Sternum,  or  breast 
bone.  —  It  is  a  flat,  nar- 
row bone  about  six  inches 
long,  situated  in  the 
median  line  in  the  front 
of  the  chest,  and  may  be 
likened  to  a  short,  flat 
sword.  It  consists  of 
three  portions.  The  up- 
per part  is  termed  the 
handle,  or  manubrium ; 
the  middle   and  largest 


Fig.  46.  —  The  Sternum.     Ventral  aspect. 
(Gerrish.) 


Chap.  V] 


THE  SKELETON 


69 


piece  is  termed  the  body,  or  gladiolus ;  the  inferior  portion  is 
termed  the  ensiform,  or  the  xiphoid  process.  On  both  sides  of 
the  upper  and  middle  pieces  are  notches  for  the  reception  of  the 
sternal  ends  of  the  costal  cartilages.  The  ensiform  or  xiphoid 
process  is  cartilaginous  in  structure  in  early  life,  but  is  more  or 
less  ossified  at  the  upper  part  in  the  adult ;  it  has  no  ribs  attached 
to  it,  but  affords  attachment  for  some  of  the  abdominal  muscles. 
Ribs  (costse) .  —  They  are  elastic  arches  of  bone,  forming  the 
chief  part  of  the  thoracic  wall  (vide  Fig.  45).  They  are  usually 
twelve  in  number  on  each  side.  They  are  all  connected  behind 
with  the  vertebrae,  and  the  first  seven  pairs  are  connected  with  the 
sternum  in  front  through  the  intervention  of  the  costal  cartilages ; 
these  first  seven  pairs  are  called  from  their  attachment  the  true 
ribs.  The  remaining  five  pairs  are  termed  false  ribs;  of  these, 
the  first  three,  eight,  nine,  and  ten  are  attached  in  front  to  the 


ANGLE. 

Fig.  47.  —  The  Eighth  Rib  of  the  Right  Side.     Viewed  from  behind.     (Geirish.) 


costal  cartilages  of  the  next  rib  above.     The  two  remaining,  being 
unattached  in  front,  are  termed  floating  ribs. 

The  convexity  of  the  ribs  is  turned  outwards  so  as  to  give 
roundness  to  the  sides  of  the  chest  and  increase  the  size  of  its 
cavity;  each  rib  slopes  downwards  from  its  vertebral  attach- 
ment, so  that  its  sternal  end  is  considerably  lower  than  its  dorsal, 
and  the  lower  border  is  grooved  for  the  accommodation  of  the 
intercostal  nerves  and  blood-vessels.  The  spaces  left  between  the 
ribs  are  called  the  intercostal  spaces. 


BONES  OF  THE  UPPER  EXTREMITIES 

Clavicle  (clavicula,  or  collar  bone)     ...      2 

Scapula  (shoulder  blade) 2 

Humerus  (arm)       2 


70 


ANATOMY  FOR  NURSES 


[Chap.  V 


(forearm) 


Ulna  — 2 
Radius  —  2 

Carpus  (wrist)         16 

Metacarpus  (palm  of  hand) 10 

Phalanges  (fingers)  28 

64 

Clavicle,  or  collar  bone.  —  It  is  a  long  bone,  placed  horizontally 
above  the  thorax.     It  articulates  with  the  sternum  by  its  inner 


:oNoio 

^TUBERCLE 


ACROMIAL 
END. 


Fig.  48.  —  The  Right  Clavicle.     Upper  surface.     (Gerrish.) 

extremity,  which  is  called  the  sternal  extremity.     Its  outer  or 
acromial  extremity  articulates  with  the  scapula.     In  the  female, 


Spine 


Coracoid  process 


Acrorr.ica  process 


Glenoid  ca\ity 


Fig.  49.  —  The  Right  Scapula,  or  Shoulder  Blade.     Viewed  Irom  behind. 

( Morrow.) 


Chap.  V] 


THE  SKELETON 


71 


-Head 


-Lesser  tuberosity 


-Surgical  neck 


the  clavicle  is  generally  less  curved,  smoother,  shorter,  and  more 
slender  than  in  the  male.  In  those  persons  who  perform  consider- 
able manual  labor,  which  brings  into  constant  action  the  muscles 
connected  with  this  bone,  it  acquires  considerable  bulk. 

Scapula,  or  shoulder  blade.  —  It  is  a  large,  flat  bone,  triangular 
in  shape,  placed  between  the  second  and  seventh,  or  sometimes 
eighth,  ribs  on  the  back  part  of  the  thorax.  It  is  unevenly  divided 
on  its  dorsal  surface  by  a  very  prominent  ridge,  the  spine  of  the 
scapula,  which  termi- 
nates in  a  large  triangU-         Anatomical  neck. 

lar  projection  called  the  Greater  tuberosity- 
acromion  process,  or 
summit  of  the  shoulder. 
Below  the  acromion  pro- 
cess, at  the  head  of  the 
shoulder  blade,  is  a  shal- 
low socket,  the  glenoid 
cavity,  which  receives 
the  head  of  the  humerus. 
Humerus,  or  arm 
bone.  —  The  humerus 
is  the  longest  and  largest 
bone  of  the  upper  limb. 
The  upper  extremity  of 
the  bone  consists  of  a 
rounded  head  joined  to 
the  shaft  by  a  con- 
stricted neck,  and' of  two 
eminences  called  the 
larger  and  smaller  tu- 
bercles, also  known  as 
tuberosities.  The  head 
articulates  with  the  gle- 
noid cavity  of  the  scap- 
ula. The  constricted  neck  above  the  tubercles  is  called  the 
anatomical  neck,  and  that  below  the  tubercles,  the  surgical 
neck,  because  it  is  so  often  fractured.  The  lower  extremity  of 
the  bone  is  flattened  from  before  backward  into  a  broad  articular 
surface  called  the  trochlea  which  is  divided  by  a  slight  ridge  so 


■  Trochlea 


Condyles 

Fig.  50.  —  The  Left  Humerus,  or  Arm  Bone. 
(Morrow.) 


72 


ANATOMY  FOR   NURSES 


[Chap.  V 


Olcrranoa 


Coronoid 


Radiu 


tliat  it  ends  in  two  condyles  by  means  of  which  it  articulates  with 

the  radius  and  ulna. 
Ulna,  or  elbow  bone.  —  It  is  placed  at  the  inner  side  (little 

finger  side)  of  the  forearm,  ])arallel  with  the  radius.     Its  upper 

extremity  presents  for  examina- 
tion two  large  curved  processes 
and  two  concave  cavities ;  the 
larger  process  forms  the  head 
of  the  elbow,  and  is  called  the 
olecranon  process.  The  smaller 
process  on  the  front  surface  is 
termed  the  coronoid,  and  the 
trochlea  of  the  humerus  fits  into 
the  cavity  —  the  great  sigmoid 
cavity  —  between  these  two  pro- 
cesses. The  lesser  sigmoid  cavity 
is  on  the  outer  side  of  the  coro- 
noid, and  receives  the  head  of  the 
radius.  The  lower  extremity  of 
the  ulna  is  of  small  size  and  ends 
in  two  prominences ;  the  outer 
one,  called  the  head,  articulates 
with  the  radius,  the  inner  one, 
named  the  styloid  process,  serves 
for  the  attachment  of  ligaments 
from  the  wrist ;  but  the  ulna  is 
excluded   from   the   wrist   bv  a 

Fig.  51.  —  The  Bo.nes  of  the  Right       •  e  n\  -i 

FoRE.\RM.     Anterior  view.      (Morrow.)     piCCe  01  hbro-cartliage. 

Radius.  —  It  is  situated  on  the 
outer  side  of  the  forearm.  The  upper  end  is  small  and  rounded, 
with  a  shallow  depression  on  its  upper  surface  for  articulation 
with  the  humerus,  and  a  prominent  ridge  about  it,  like  the  head  of 
a  nail,  by  means  of  which  it  rotates  within  the  lesser  sigmoid  cavity 
of  the  ulna.  The  lower  end  of  the  radius  is  large,  and  forms  the 
chief  part  of  the  wrist. 

Carpus,  or  wrist.  —  The  wrist  joint  is  composed  of  eight  small 
bones  (ossa  carpi)  united  by  ligaments ;  they  are  arranged  in  two 
rows,  and  are  closely  welded  together,  yet  by  the  arrangement 
of  their  ligaments  allow  of  a  certain  amount  of  motion.     They 


Chap.  V] 


THE   SKELETON 


73 


THIRD  PHALANX 


Fig.  52.  —  The  Bones  of  the  Right  Hand.     Palmar  aspect.     (Gerrish.) 

afford  origin  by  their  palmar  surface  to  most  of  the  short  muscles 
of  the  thumb  and  little  finger,  and  are  named  as  follows :  — 


row. 

Scaphoid 

.     1 

2d  row.     Trapezium     . 

.     1 

Semilunar 

.     1 

Trapezoid 

.     1 

Cuneiform     . 

.     1 

Os  Magnum  . 

.     1 

Pisiform 

.     1 

Unciform 

.     1 

8 

74 


ANATOMY  FOR   NURSES 


[Chap.  V 


Metacarpus,  or  body  of  hand.  —  Eacli  metacarpus  is  formed 
by  five  bones  (ossa  metacarpaliaj.  The  bones  are  curved  longi- 
tudinally, so  as  to  be  convex  behind,  and  concave  in  front.  They 
articulate  at  their  bases  with  the  second  row  of  carpal  bones  and 
with  each  other.  The  heads  of  the  bones  articulate  with  the  bases 
of  the  first  row  of  the  phalanges. 

Phalanges,  or  digits.  —  They  are  the  bones  of  the  fingers ; 
and  are  fourteen  in  number  in  each  hand,  three  for  each  finger, 
and  two  for  the  thumb.  The  first  row  articulates  with  the  meta- 
carpal bones  and  the  second  row  of  phalanges ;  the  second  row, 
with  the  first  and  third  ;    and  the  third,  with  the  second  row. 


BONES  OF  THE   LOWER  EXTREIVIITIES 

Hip  bones  (ossa  coxa?  or  ossa  innominata)     .     .  2 

Femur  (thigh  bone) 2 

Patella  (knee-cap) 2 

Tibia    (shin  bone)  2)  . 

Fibula  (calf  bone)  2)    ^^         

Tarsus  (ankle,  or  root  of  foot) 14 

Metatarsus  (sole  and  instep)        10 

Phalanges  (toes) 28 

62 

^„,,.^_-^^  The   bones  of  the  lower  ex- 

^/^^  ^^^x  tremities  correspond  to  a  great 

^''  ^^  extent  with  those  of  the  upper 

extremities,  and  bear  a  rough  re- 
l[i  (  semblance    to    them,    but    are 

'  heavier    and    more   firmly  knit 

together. 

Hip  bone,  or  os  coxae. —  It  is 
a   large,   irregular-shaped  bone, 
^*(»"*.     TC?     which,  with  its  fellow  of  the  op- 
I      IW'^     posite  side,  forms  the  sides  and 
(         %,  front  wall  of  the  pelvic  cavity. 

■^^^>..-i->^  ^"  young  subjects  it  consists  of 

**  three   separate   parts,    and    al- 

Fig.  53^- Development  OF  THE  Hip    though  in  the  adult  these  have 
UONE.     bhowing  the  union  of  the  three 
portions  in  the  acetabulum.     (Gerrish.)     become  United,  it  is  USUal  to  de- 


Chap.  Y]  THE   SKELETON  75 

scribe  the  bone  as  divisible  into  three  portions  :  (1)  the  ihum  (plural 
ilia),  (2)  the  ischium  (plural  ischia),  (3)  the  pubis  (plural  pubes). 
The  ilium  is  the  upper  broad  and  expanded  portion  which  forms 
the  prominence  of  the  hip.  The  ischium  is  the  lower  and  strongest 
portion  of  the  bone,  while  the  pubes  is  that  portion  which  forms 
the  front  of  the  pelvis.  Where  these  three  portions  of  the  bone 
meet  and  finally  ankylose  is  a  deep  socket,  called  the  acetabulum, 
into  which  the  head  of  the  femur  fits.  Other  points  of  special 
interest  to  note  in  the  hip  bones  are  :  — 

(1)  The  spinous  process  formed  by  the  projection  of  the  crest 
of  the  ilium  in  front,  which  is  called  the  anterior  superior  spinous 
process,  and  which  is  a  well-known  and  convenient  landmark 
in  making  anatomical  and  surgical  measurements. 

(2)  The  largest  foramen  in  the  skeleton,  known  as  the  thyroid 
foramen,  situated  between  the  ischium  and  pubis. 

(3)  The  symphysis  pubis,  or  pubic  articulation,  which  also 
serves  for  a  convenient  landmark  in  making  measurements. 

The  pelvis.  —  The  pelvis,  so  called  from  its  resemblance  to  a 
basin,  is  stronger  and  more  massively  constructed  than  either  the 


Female  Pelvis. 


cranial  or  the  thoracic  cavity.  It  is  composed  of  four  bones,  the 
two  hip  bones  forming  the  sides  and  front,  the  sacrum  and  coccyx- 
completing  it  behind.     It  is  divided  by  a  narrowed  bony  ring  into 


76 


ANATOMY  FOR  NURSES 


[Chap.  V 


the  large  (false),  and  small  (true)  pelvis.  The  narrowed  bony 
ring  which  is  the  dividing  line  is  spoken  of  as  the  brim  of  the  pelvis, 
the  ilio-pedineal  line,  and  the  strait.  The  large  pelvis  is  all  that 
expanded  portion  of  the  pelvis  situated  above  the  brim  ;  it  forms 
an  incomplete  or  false  basin.  The  small  pelvis  is  all  that  portion 
situated  below  the  brim.  Its  cavity  is  a  little  wider  in  every  direc- 
tion than  the  brim  itself,  while  the  large  pelvis  is  a  great  deal  wider. 
The  small  bony  pelvis  is  a  basin  with  incomplete  walls  of  bone, 


.    Fig.  55.  —  Male  Pelvis. 

the  bottom  of  which  is  composed  of  the  softer  tissues,  muscles, 
and  ligaments.  The  opening  of  the  small  pelvis,  i.e.  the  space 
just  above  the  brim,  is  called  the  inlet,  and  the  opening  below  is 
called  the  inferior  strait,  or  outlet. 

The  female  pelvis  differs  from  that  of  the  male  in  those  particu- 
lars which  render  it  better  adapted  to  pregnancy  and  parturition. 
It  is  more  shallow  than  the  male  pelvis,  but  wider.in  every  direction. 
The  inlet  and  outlet  are  larger,  the  bones  are  lighter  and  smoother, 
and  the  coccyx  is  more  movable.  As  can  be  seen  by  looking  at 
Fig.  54  and  Fig.  55  a  distinctive  anatomical  difference  is  that 
the  sub-pubic  angle  in  a  male  is  less  than  a  right  angle,  and  in  the 
female  it  is  greater  than  a  right  angle. 


Chap.  Y] 


THE  SKELETON 


77 


Femur,  or  thigh  bone.  — 

It  is  the  longest,  largest,  and 
strongest  bone  in  the  skele- 
ton. The  upper  extremity 
of  the  femur,  like  that  of 
the  humerus,  consists  of  a 
rounded  head  joined  to  the 
shaft  by  a  constricted  neck, 
and  of  two  eminences, 
called  the  greater  and  lesser 
trochanters.  The  head  ar- 
ticulates with  the  cavity  in 
the  hip  bone,  called  the 
acetabulum.  The  lower  ex- 
tremity of  the  femur  is 
larger  than  the  upper,  is 
flattened  from  before  back- 
wards, and  divided  into  two 
large  eminences  or  condyles 
by  an  intervening  notch. 
It  articulates  with  the  tibia 
and  the  patella,  or  knee- 
cap. In  the  erect  position 
it  is  not  vertical,  being  sep- 
arated from  its  fellow  by 
a  considerable  interval, 
which  corresponds  to  the 
entire  breadth  of  the  pelvis, 


Fig.  57.  —  The  Right  Patella. 
surface.     (Gerrish.) 


Condyles 

Fig.  56.  —  The  Right  Femur,  or  Thigh 
Bone.     Anterior  view.     (Morrow.) 

but  the  bone  inclines  gradually  down- 
ward and  inward,  so  as  to 
approach  its  fellow  towards 
its  lower  part,  in  order  to 
bring  the  knee-joint  near  the 
line  of  gravity  of  the  body. 
The  degree  of  inclination  va- 
ries in  different  persons,  and 
is  greater  in  the  female  than 
the  male,  on  account  of  the 
greater  breadth  of  the  pelvis. 
Patella,  or  knee-cap.  —  It 


Ventral 


78 


ANATOMY  FOR   NURSES 


[Chap.  V 


^^  tuberosity 


is  the  largest  sesamoid  bone  in  the  body.  It  is  small,  flat,  tri- 
angular in  shape,  and  placed  in  front  of  the  knee-joint,  which 
it  serves  to  protect.  It  articulates  with  the  two  condyles  of  the 
femur,  and  is  separated  from  the  skin  by  a  bursa.  (See  page  131.) 
Tibia,  or  shin  bone.  —  Is  situated  at  the  front  and  inner  side 
of  the  leg.  The  upper  extremity  is  large,  and  expanded  into  two 
lateral  eminences  with  concave  surfaces,  which  receive  the  con- 
dyles of  the  femur.     The  lower  extremity  is  much  smaller  than  the 

upper ;  it  is  prolonged  down- 
wards on  its  inner  side  into  a 
strong  process,  the  medial  (or 
inner)  malleolus.  It  articu- 
lates with  the  fibula  and  one 
of  the  bones  of  the  ankle.  (In 
the  male,  its  direction  is  verti- 
cal and  parallel  with  the  bone 
of  the  opposite  side;  but  in 
the  female  it  has  a  slight 
oblicpie  direction  outwards,  to 
compensate  for  the  oblique  di- 
rection of  the  femur  inwards.) 
Fibula,  or  calf  bone.  —  Is 
situated  at  the  outer  side  of 
the  leg.  It  is  the  smaller  of 
the  two  bones,  and,  in  propor- 
tion to  its  length,  the  most 
slender  of  all  the  long  bones ; 
it  is  placed  nearly  parallel  with 
the  tibia.  The  upper  ex- 
tremity consists  of  an  irregu- 
lar quadrate  head  by  means  of 
which  it  articulates  with  the 
tibia.  The  lower  extremity  is  prolonged  downwards  into  a  pointed 
process,  the  lateral  (or  external)  malleolus,  which  lies  just  beneath 
the  skin.  It  articulates  with  the  tibia  and  one  of  the  bones  of  the 
ankle. 

Tarsus.  —  The  tarsus  is  composed  of  seven  small  bones  united 
by  ligaments,  but  the  tarsal  bones  differ  from  the  carpal  in  being 
larger  and  more  irregularly  shaped.     The  largest  and  strongest 


Outer 
malleolus 


Fl<i.  5S. 


Inner 
in:iilcolus 


The  Bones  of  the  Rk.ht  Leg. 
(Morrow.) 


riBST    PHALANX— 
or    riFTH    TOE 


FIRST    PHALANX 
OF    HALLUX 


Fig.  59. -THE  BONES  OF  THE 


Right  Foot. 


79 


Viewed  from  above.     (Gerrish.) 


80 


ANATOMY  FOR  NURSES 


[Chap.  V 


of  the  tarsal  bones  is  called  the  calcaneum,  or  heel  bone  ;   it  serves 
to  transmit  the  weight  of  the  body  to  the  ground,  and  forms  a 
strong  lever  for  the  muscles  of  the  calf  of  the  leg. 
The  names  are  as  follows :  — 

Calcaneum 

Astragalus 

Cuboid 

Scaphoid 

I^xternal  cuneiform 

jVIiddie  cuneiform        

Internal  cuneiform 

Metatarsus,  or  sole  and  instep  of  foot,  is  formed  by  five  bones. 
These  metatarsal  bones  closely  resemble  the  metacarpal  bones 
of  the  hand.  Each  bone  articulates  with  the  tarsal  bones  by 
one  extremity,  and  by  the  other  with  the  first  row  of  phalanges. 

Phalanges,  or  digits.  —  Both  in  number  and  general  arrange- 
ment resemble  those  in  the  hand,  there  being  two  in  the  great 
toe  and  three  in  each  of  the  other  toes. 


Bones 


Function 


Classification . 


SUMMARY 

1 .  Organs  of  support. 

2.  Instruments  of  locomotion. 

3.  Framework  of  hard  material. 

4.  Afford  attachment  to  soft  parts. 

5.  Shelter  dehcate  structures. 
.  6.  Shape  to  whole  body. 

1.  Long. 

2.  Short. 

3.  Flat. 

4.  Irregular. 


Chap.  V] 


THE  SKELETON 


81 


TABLE  OF  THE  BONES 
HEAD 


Cranium 

Occipital 1 

Parietal 2 

Frontal 1 

Temporal 2 

Sphenoid 1 

Ethmoid 1 

8 


Face 

Nasal 2 

Lacrimal 2 

Vomer 1 

Malar 2 

Palate 2 

Inferior  turbinated      ...  2 

Maxilla     .     .■ 2 


Mandible 


J. 
14 


f  Malleus 
Ear  I  Incus  . 
[  Stapes 


Hyoid  bone  in  the  neck 


TRUNK 


Cervical  . 
Thoracic  . 
Vertebrae  {  Lumbar  . 
Sacral 
.  Coccygeal 
Ribs  .  . 
Sternum 


Child 
7 
12 
5 
5 
4  =  33 


Adult 

7 
12 

5 

1 

1  =  26 
.     .     24 


Upper  Extremity 

Clavicle  . 

Scapula  . 

Humerus 

Ulna       . 

Radius    . 

Scaphoid 

Semilunar 

Cuneiform 

Pisiform 

Trapezium 

Trapezoid 

Os  magnum 

Unciform 

Metacarpus     .     . 

Phalanges   .     .     . 


32  X  2  =  64 


Carpus 


Lower  Extremity 
Hip  bone  (os  coxse) .     . 

Femur 

Patella 

Tibia 

Fibula 


5 
32 


r  Calcaneum     .     . 

Astragalus      .     . 

Cuboid      .     .     . 

Tarsus  { Scaphoid    .     .     . 

External  cuneiform 
Middle  cuneiform 
.  Internal  cuneiform 

Metatarsus 5 

Phalanges       14 

31 


31  X  2  =  62 


CHAPTER  VI 

ARTICULATIONS 

Articulations  or  joints.  —  The  various  bones  of  which  the 
skeleton  consists  are  connected  together  at  different  parts  of  their 
surfaces,  and  such  connections  are  called  articulations  or  joints. 

CLASSIFICATION 

Joints  are  classified  as  :  — 

1.  Synarthroses,  or  immovable  joints. 

2.  Amphiarthroses,  or  slightly  movable  joints. 

3.  Diarthroses,  or  freely  movable  joints. 

In  all  instances  some  softer  substance  is  placed  between  the  bones, 
uniting  them  together  or  clothing  the  opposed  surfaces ;  but  the 
manner  in  which  the  several  pieces  of  the  skeleton  are  thus  con- 
nected varies  to  a  great  degree. 

SYNARTHROSES,   OR  IMMOVABLE  JOINTS 

The  bones  are  connected  by  fibrous  tissue  or  cartilage. 
The  bones  of  the  cranium  and  the  facial  bones  (with  the  ex- 
ception  of    the    lower   jaw)    have    their   adjacent   surfaces   ap- 
plied   in    close    contact,    with    only   a    thin 
layer  of  fibrous  tissue  placed  between  their 
margins. 

In  most  of  the  cranial  bones  this  union 
occurs  by  means  of  toothed  edges  which 
dovetail  into  one  another  and  form  jagged 
lines  of  union  known  as  sutures. 
orDE">n^TED.^SDTURE.  ^lic  thrcc  most  important  sutures  are  as 
follows :  — 

(1)  Coronal. — The  line  of  union  between  the  frontal  and 
parietal  bones. 

(2)  Lambdoidal.  —  The  line  of  union  betw^een  the  parietal  and 
occipital  bones. 

82 


Chap.  VI] 


ARTICULATIONS 


83 


(3)  Sagittal  suture.  —  This  begins  at  the  base  of  the  nose, 
extends  along  the  middle  line  on  the  top  of  the  crown,  separates 
the  frontal  bone  into  two  parts/  the  parietal  bones  from  each 
other,  and  ends  at  the  posterior  fontanelle. 


Fig.  61.  —  Diameters  and  Landmarks  of  the  Fcetal   Skull.     Upper  sur- 
face.     (Edgar.) 

Synchondrosis  is  usually  a  temporary  form  of  joint.  The 
cartilage  between  the  bones  ossifies  before  adult  life.  Example : 
the  union  of  the  sphenoid  and  occipital  bones. 

1  That  portion  of  the  sagittal  suture  which  separates  the  frontal  bone  into  two 
parts  is  often  called  the  frontal  suture.     (See  Fig.  61.) 


84 


ANATOMY  FOR  NURSES 


[Chap.  VI 


Fig.    62.  —  Diameters  and  I.andmahks  of  the  Fcetal  Skull.     Posterior 
surface.     (Edgar.) 


AMPHIARTHROSES,   OR   SLIGHTLY  MOVABLE  JOINTS 

The  above  terms  apply  to  joints  that  permit  of  slight  movement 
and  include  two  varieties:    (1)  symphysis,  and  (2)  syndesmosis. 

Symphysis.  —  In  this  form  of  articulation  the  bony  surfaces  are 
joined  together  by  broad,  flattened  disks  of  fibro-cartilage,  as  in 

the  articulations  between  the  bodies  of 
the  vertebrse.  These  intervertebral  disks 
being  compressible  and  extensile,  the 
spine  can  be  moved  to  a  limited  extent 
in  every  direction.  In  the  pelvis  the 
articulation  between  the  two  pubic  bones 
(symphysis  pubis),  and  between  the  sac- 
rum and  ilia  (sacro-iliac  articulation), 
are  slightly  movable.  The  pubic  bones 
are  united  by  a  disk  of  fibro-cartilage  and  by  ligaments.  In  the 
sacro-iliac  articulation  the  sacrum  is  united  more  closely  to  the 


Fio.  63.  —  A  Slightly 
Movable  Joint,  a,  b,  disk 
of  fibro-cartilage  ;  c,  articular 
cartilage ;   d,  bone. 


Chap.  VI] 


ARTICULATIONS 


85 


ilia,  the  articular  surfaces  being  covered  by  cartilage  and  held 
together  by  ligaments. 

The  fibro-cartilage  between  these  joints  (symphysis  pubis  and 
sacro-iliac)  becomes  thickened  and  softened  during  pregnancy 
and  allows  of  a  certain  limited  motion  which  is  essential  to  a  nor- 
mal parturition. 

Syndesmosis.  —  When  the  bony  surfaces  are  united  by  an 
interosseous  ligament,  as  in  the  lower  tibio-fibular  articulation,  it 
is  called  syndesmosis. 


5VN0VIAL   FOLD 


DIARTHROSES,   OR  FREELY  MOVABLE  JOINTS 

This  division  includes  the  complete  joints,  and  are  the  only 
joints  in  which  the  three  following  conditions  are  found :  — 

(1)  The  bones  are  united  by  fibrous  ligaments,  forming  more 
or  less  perfect  capsules.  The  ligaments  are  not  always  so  tight 
as  to  maintain  the  bones  in  close  contact  in  all  positions  of  the 
joint,  but  are  rather  tightened  in  some  positions  and  relaxed 
in  others,  so  that  in  many  cases  they  are  to  be  looked  on  chiefly 
as  controllers  of  movements,  and  not  as  serving  solely  to  hold 
the  bones  together.  The  bones 
are  partly  held  together  in  these 
joints  by  atmospheric  pressure 
and  largely  by  the  surrounding 
muscles. 

(2)  A  secreting  membrane 
(synovial)  lines  the  capsule  and 
is  so  arranged  that  it  dips  in 
between  the  edges  of  the  oppos- 
ing articular  cartilages.  (See 
Fig.  64.) 

(3)  Each  articular  end  of  the 

bone  is  covered  by  hyaline  cartilage,  which  provides  surfaces  of 
remarkable  smoothness,  and  these  surfaces  are  lubricated  by  the 
synovial  fluid  secreted  from  the  delicate  synovial  membrane  which 
lines  the  cavity  of  the  joint. 

The  varieties  of  joints  in  this  class  have  been  determined  by 
the  kind  of  motion  permitted  in  each.     They  are  as  follows :  — 

(1)  Gliding  joint.  —  The  articular  surfaces  are  nearly  flat,  and 


Fig.  G4.  —  A  (Vj.mplete  Joint.  The 
synovial  membrane  is  represented  by 
dotted  lines. 


86  ANATOMY   FOR   NURSES  [Chap.  VI 

admit  of  only  a  limited  amount  of  gliding  movement,  as  in  the 
joints  between  the  articular  processes  of  the  vertebra?. 

(2)  Hinge  joint.  —  The  articular  surfaces  are  of  such  shape  as 
to  permit  of  movement  to  and  fro  in  one  plane  only,  like  a  door 
on  its  hinges.  These  movements  are  called  flexion  and  extension, 
and  may  be  seen  in  the  articulation  of  the  arm  with  the  forearm, 
in  the  ankle  joint,  and  in  the  articulations  of  the  phalanges. 

(3)  Ball  and  socket  joint.  —  In  this  form  of  joint  a  more  or 
less  rounded  head  is  received  into  a  cup-like  cavity,  as  the  head 
of  the  femur  into  the  acetabulum,  and  the  head  of  the  humerus 
into  the  glenoid  cavity  of  the  scapula.  Movement  can  take 
place  freely  in  any  direction,  but  the  shallower  the  cup,  the 
greater  the  extent  of  motion.  The  shoulder  joint  is  the  most 
freely  movable  joint  in  the  body. 

(4)  Pivot  joint.  —  In  this  form,  one  bone  rotates  around  another 
which  remains  stationary,  as  in  the  articulation  of  the  atlas  with 
the  axis  (epistropheus)  and  in  the  articulation  of  the  ulna  and 
radius.  In  the  articulation  of  the  ulna  and  radius  the  ulna  re- 
mains stationary,  and  the  radius  rotates  freely  around  its  upper 
end.  The  hand  is  attached  to  the  lower  end  of  the  radius,  and 
the  radius,  in  rotating,  carries  the  hand  with  it ;  thus,  the  palm 
of  the  hand  is  alternately  turned  forward  and  backward.  When 
the  palm  is  turned  forward,  or  upward,  the  attitude  is  called 
supination  ;   when  backward,  or  downward,  pronation. 

(5)  Condyloid  joint.  —  When  an  oval-shaped  head,  or  condyle, 
of  a  bone  is  received  into  an  elliptical  cavity,  it  is  said  to  form 
a  condyloid  joint.  An  example  of  this  kind  of  joint  is  found  in 
the  metacarp()-])halangeal  articulations.  The  rounded  heads  of 
the  metacarjial  bones  are  rcrcjved  in  the  elliptical-shaped  bases 
of  the  phalanges. 

(6)  Saddle  joint.  —  In  this  joint  the  articular  surface  of  each 
bone  is  concave  in  one  direction,  and  convex  in  another,  at  right 
angles  to  the  former.  A  man  seated  in  a  saddle  is  "  articu- 
lated "  with  the  saddle  by  such  a  joint.  For  the  saddle  is  con- 
cave from  before  backwards,  and  convex  from  side  to  side,  while 
the  man  presents  to  it  the  concavity  of  his  legs  astride,  from 
side  to  side,  and  the  convexity  of  his  seat,  from  before  back- 
wards. The  metacarpal  bone  of  the  thumb  is  articulated  with 
the  trapezius  of  the  carpus  by  a  saddle  joint.     Both  the  condy- 


Chap.  YI] 


ARTICULATIONS 


87 


loid  and  the  saddle  joints  admit  of  motion  in  every  direction  except 
that  of  axial  rotation. 

The  different  kinds  of  movement  of  which  bones  thus  con- 
nected are  capable  are  :  — 

1.  Flexion.  —  A  limb  is  flexed,  when  it  is  bent. 

2.  Extension.  —  A  limb  is  extended,  when  it  is  straightened  out. 

3.  Abduction.  —  This  term  generally  means  drawn  away  from 
the  middle  line  of  the  body. 

4.  Adduction.  —  This  term  generally  means  brought  to  or 
nearer  the  middle  line  of  the  body. 

Both  abduction  and  adduction  have  a  different  meaning  when 
used  with  reference  to  the  fingers  and  toes.  In  the  hand  the 
imaginary  line  is  supposed  to  be  drawn  through  the  middle  finger ; 
and  in  the  foot  through  the  second  toe. 

5.  Rotation.  —  INIeans  made  to  turn  on  its  own  axis. 

6.  Circumduction.  —  Means  made  to  describe  a  conical  space 
by  rotation  around  an  imaginary  axis. 

No  part  of  the  body  is  capable  of  perfect  rotation,  as  a  wheel, 
for  the  simple  reason  that  such  motion  w^ould  necessarily  tear 
asunder  all  the  vessels,  nerves,  muscles,  etc.,  which  unite  it  with 
other  parts. 

Sprain.  —  A  wrenching  or  twisting  of  a  joint  accompanied 
by  a  stretching  or  tearing  of  the  ligaments  or  tendons  is  called 
a  sprain. 

Dislocation.  —  If  in  addition  to  a  sprain,  the  bone  is  displaced, 
the  injury  is  called  a  dislocation. 


SUMMARY 

Articulations  or  Joints  —  connections  existing  between  bones. 

1.  Sutura. — Articulations    by 


Synarthrosis, 

Bones  are  con- 

or 

nected  by  fi- 

Immovable 

brous    tissue 

Joint 

or  cartilage. 

pro- 


cesses and  indentations  interlocked 
together.  A  thin  layer  of  fibrous 
tissue  is  interposed  between  the 
bones.  Sutures  may  be  dentated, 
dove-tailed ;  serrated,  saw-like ; 
squamous,  scale-Uke ;  harmonic, 
smooth;  and  grooved,  for  the  re- 
ception of  thin  plates  of  bone. 
,  Synchondrosis. — Temporary 
joint.  Cartilage  between  bones 
ossifies  in  adult  life. 


88 


ANATOMY   FOR   NURSES 


[Chap.  VI 


Amphiarthrosis, 

or  Slightly 

Movable 

Joint 


Bones  are  con- 
nected by 
ili.sks  of  car- 
tilage or  in- 
terosseous 
ligaments. 


'  1.  Symphysis.  —  The  bones  are 
united  bj'  a  plate  or  disk  of  fibro- 
cartilage  of  considerable  thickness. 
Syndesmosis.  —  The  bony  surfaces 
are  united  by  an  interosseous  liga- 
ment, as  in  the  lower  tibio-fibular 
articulation. 


Diarthrosis,  or 

Movable 

Joint 


Movement . 


,  Fibrous  liga- 
ments form- 
ing a  capsule. 
Synovial 
ni  e  m  b  r  a  n  e 
lining  fibrous 
capsule. 
Hyaline  car- 
tilage cover- 
ing articular 
ends  of  bones. 


Flexion. 
Extension. 
Abduction. 
Adduction. 
Rotation. 
.  Circumduction. 


1.  Arthrodia.  —  Gliding  joint ;  artic- 
ulates by  i)lane  surfaces  which  glide 
upon  each  other. 

2.  Ginglymus.  —  Hinge  or  angular 
joint ;  moves  backward  and  for- 
ward in  one  plane. 

3.  Enarthrosis.  —  Ball  and  socket 
joint ;  articulates  bj'  a  globular 
head  in  a  cup-like  cavity. 

4.  Trochoides.  —  Pivot  joint ;  articu- 
lates by  a  pivot  process  turning 
within  a  ring,  or  by  a  ring  turning 
round  a  pivot. 

5.  Condylarthrosis.  —  Condyloid 
joint ;  ovoid  head  received  into 
elliptical  cavity. 

6.  Reciprocal  Reception.  —  Saddle 
joint ;  articular  surfaces  are  con- 
cavo-convex. 


CHAPTER   VII 

MUSCULAR    TISSUE:    CLASSIFICATION;     PROMINENT    SKELETAL 

MUSCLES 

MUSCULAR  TISSUE 

This  is  the  tissue  by  means  of  which  the  movements  of  the 
body  and  its  component  parts  are  produced.  It  constitutes  the 
fleshy  parts,  enters  into  the  structure  of  many  of  the  internal 
organs,  and  forms  a  large  proportion  of  the  weight  of  the  whole 
body.  The  following  has  been  calculated  for  a  man  of  one  hun- 
dred and  fifty  pounds'  weight  from  the  tables  of  Liebig :  — • 

Skeleton  28  pounds. 

Blood  12  pounds. 

Viscera 

Skin  48  pounds. 

Fat        J 

Muscles  62  pounds. 

Muscular  tissue,  like  every  other  tissue,  is  composed  of  cells  and 
intercellular  substance,  with  this  special  difference  that  the  cells 
become  elongated  and  develop  into  fibres.  The  intercellular 
substance  consists  of  a  small  amount  of  cement,  which  helps  to 
hold  the  fibres  together.  The  fibres  are  really  bound  into  bundles 
by  connective  tissue  which  forms  a  supporting  framework. 

CLASSIFICATION 

Muscle  fibres  are  of  three  distinct  kinds,  and  we  therefore  dis- 
tinguish three  varieties  of  muscular  tissue  :  — 

1.  Striated  or  cross-striped ; 

2.  Non-striated  or  plain  ; 

3.  Cardiac. 

Striated  or  cross-striped  muscular  tissue.  —  This  tissue  is 
called  striated  because  it  is  distinctly  marked  by  striae,  or  parallel 
cross  stripes.     It  is  also  called  skeletal  because  it  forms  the  muscles 

89 


90 


ANATOMY  FOR  NURSES 


[Chap.  VII 


Fig.  65.  —  Dia- 
GRA.M  OF  Muscle 
Fibre  with  Sar- 
coLEM.MA  At- 
tached. 


which  are  attached  to  the  skeleton,  and  voluntary  because  it  is 
nearly  always  under  the  control  of  the  will.  It  is  composed  of 
long,  slender  fibres  measuring  on  an  average  gj^ 
inch  (0.050  mm.)  in  diameter,  but  having  a  length 
of  an  inch  or  more. 

Each  fibre  consists  of  three  distinct  elements :  — 

(1)  Contractile  substance,  forming  the  centre  and 
making  up  most  of  the  bulk  of  the  fibres ; 

(2)  Nuclei,  which  lie  scattered  upon  the  surface 
of  the  contractile  substance  ; 

(3)  The  sarcolemma,  a  thin,  structureless  tube 
which  tightly  encloses  the  contractile  substance 
and  the  nuclei. 

As  each  fibre  is  developed  from  a  single  cell  and 
contains  a  number  of  nuclei,  we  may  regard  it  as 
a  multinuclear  cell  of  elongated  form.  The  muscle 
fibres  lie  closely  packed,  their  ends  lapping  over 
on  to  adjacent  fibres  and   forming   bundles.     A 

delicate  connective  tissue   penetrates  between 

the  fibres,    surrounds   the    small   bundles   and 

groups  them  into  larger  bundles.     Connective 

tissue    also  surrounds  the  larger  bundles  and 

forms  a  covering  for  the  whole  muscle.     Thus  it 

will  be  seen  that  connective  tissue  forms  a  sup- 
porting framework  for  muscular  tissue. 

All  of  the  muscles  described  in  this  chapter 

are  striated  or  skeletal. 

Non-striated  or  plain  muscular  tissue.  —  This 

tissue  is  called  plain  or  non-striated  because  it 

does  not   exhibit   parallel   transverse    strice   or 

stripes.     It   is   also   called   visceral   because   it 

constitutes  a  large  portion  of  the  substance  of 

many  of  the  viscera,  and  involuntary  because  it 

is  usually  withdrawn  from  the  control  of  the 

will.     It   is   composed  of   elongated   fibre-cells 

containing  a  single  elongated  nucleus.     These 

fibre-cells  are  always  shorter  than  the  fibres  of 

striated  tissue.      They  lie  side  by  side  or  lay  over  one  another  at 

the  ends   and  are  joined  together  by  a  small  amount  of  cement 


Fig.  66.  —  Fibre- 
cells  OF  Plain 
Muscular  Tissue. 
(Highly    magnified.) 


Chap.  VII]  MUSCULAR  TISSUE  91 

substance.  The  fibre-cells  are  variously  grouped  in  different 
parts  of  the  body ;  sometimes  crowded  together  in  solid  bundles 
which  are  arranged  in  layers  and  surrounded  by  connective  tis- 
sue, as  in  the  intestines ;  sometimes  arranged  in  narrow,  inter- 
lacing bundles,  as  in  the  bladder ;  sometimes  wound  in  single  or 
double  layers  around  the  blood-vessels ;  and  again  running  in 
various  directions  and  associated  with  bands  of  connective  tissue, 
they  form  large,  compact  masses,  as  in  the  uterus. 

Cardiac  muscular  tissue.  —  This  variety  of  muscular  tissue  is 
found  only  in  the  heart  substance.  It  is  involuntary,  but  is 
striated,  though  not  as  distinctly  as  skeletal  muscle.  It  is  made 
up  of  fibres  which  are  short,  contain  just  one  nucleus,  and  no 
sarcolemma.  The  fibres  are  grouped  in  bundles  which  are  nearly 
square,  and  fine  fibrils  from  each  cell  help  to  hold  the  bundles 
together.  The  bundles  are  really  held  together  by  connective 
tissue,  which  forms  a  supporting  framework  in  the  heart,  just  as 
it  does  in  skeletal  and  visceral  muscle. 

Stimuli.  —  This  term  is  used  to  describe  influences  which  stimu- 
late muscle  fibres.  They  may  be  chemical,  mechanical,  thermal, 
electrical,  or  nervous.  From  the  standpoint  of  physiology  the 
nervous  impulse  is  the  most  important. 

Characteristics.  —  Muscular  tissue  is  highly  specialized  and 
exhibits  irritability,  contractility,  extensibility,  elasticity,  and 
tonicity. 

Irritability  has  been  defined  as  the  response  of  a  tissue  to  a 
stimulus.  Nervous  tissue  and  certain  epithelial  cells  as  well  as 
muscular  tissue  possess  this  property.  The  response  of  any 
tissue  to  stimulation  is  to  perform  its  special  function,  and  in  the 
case  of  muscular  tissue  this  response  takes  the  form  of  contraction 
and  is  known  as  muscular  contractility.  Each  individual  fibre 
becomes  shorter  and  thicker,  and  thus  the  whole  muscle  becomes 
shorter  and  thicker.  The  function  of  the  connective  tissue  frame- 
work is  passive  and  may  be  likened  to  that  of  a  harness,  through 
which  all  the  numerous  contractile  fibres  are  enabled  to  unite 
their  efforts.  Contraction  of  the  muscle  tends  to  bring  together 
its  two  ends  with  whatever  may  be  attached  to  them.  Thus 
the  contraction  of  certain  muscles  of  the  arm  will  shorten  the 
muscles,  shorten  the  distance  between  their  ends,  and  flex  the 
forearm. 


92  ANATOMY   FOR   NURSES  [Chap.  \II 

Exiensibility  of  a  li\'ing  muscle  means  that  it  can  be  stretchetl 
or  extended,  and  elasticity  means  that  it  readily  returns  to  its  orig- 
inal form.  Normally,  the  skeletal  muscles  are  in  a  condition  of 
slight  tension,  being  stretched  from  bone  to  bone.  This  condition 
is  of  importance  in  two  ways :  (1)  smoothness  of  movement  is 
dependent  upon  it ;  (2)  a  stretched  muscle  will  contract  more 
cjuickly  than  one  that  is  relaxed.  To  understand  the  first  state- 
ment it  is  important  to  remember  that  skeletal  muscles  are  usually 
arranged  in  antagonistic  groups,  one  of  which  opposes  another. 
Thus  the  muscles  located  on  the  anterior  surface  of  the  arm  and 
forearm  are  called  flexors,  and  those  located  on  the  posterior  sur- 
face are  called  extensors.  The  action  of  the  flexors  is  to  bend  the 
arm,  the  action  of  the  extensors  is  to  extend  or  straighten  the  arm. 
When  stimulated,  either  group  of  muscles  must  overcome  the  resist- 
ance of  the  opposing  group.  Therefore  contraction  takes  place 
more  slowly  and  evenly,  and  smoothness  of  movement  is  the  result. 

Under  normal  conditions  there  is  a  constant  and  insensible 
tendency  to  contract  called  tonicity.  It  is  really  a  mild,  sustained 
contraction,  and  though  it  may  vary  in  degree,  it  is  rarely  absent 
altogether.  Tone  in  the  skeletal  muscles  gives  them  a  certain 
firmness  and  maintains  a  .slight  steady  pull  upon  their  attach- 
ments. It  is  not  likely  to  result  in  movement  on  account  of  the 
action  of  an  antagonistic  muscle.  In  fractures  the  over-riding  of 
the  broken  ends  of  a  bone  is  often  due  to  the  contraction  of  the 
muscle,  that  is  the  result  of  its  tonicity.  This  property  is  of 
importance  in  several  ways:  (1)  in  connection  with  elasticity 
it  promotes  a  quicker  response  to  stimulation,  (2)  it  assists  in 
maintaining  the  circulation  of  the  blood  and  hinph,  and  (3)  it 
assists  in  the  regulation  of  nutrition  and  body  heat.  As  previously 
staled  tonicity  may  vary  in  degree.  Increase  in  the  degree  may 
follow  (1)  muscular  exercise,  (2)  mental  exercise,  and  (3)  lower- 
ing of  the  surrounding  temperature.  The  effect  of  a  cold  bath  is 
a  familiar  example  of  the  last. 

Blood-vessels  and  nerves.  —  All  varieties  of  muscular  tissue 
are  well  supplied  with  blood-vessels  and  nerves.  The  blood- 
vessels that  supply  blood  to  the  muscles  are  supported  and  carried 
by  the  connective  tissue.  They  do  not  penetrate  into  the  cells, 
but  each  cell  is  bathed  in  lymph  which  exudes  from  the  blood- 
vessels.    The  cells  take  from  the  lymph  the  materials  they  need 


Chap.  VII]  MUSCULAR  TISSUE  93 

and  give  up  to  the  lymph  the  waste  substances  that  are  the  result 
of  their  activities. 

In  order  to  understand  the  nerve  supply  it  is  necessary  to 
become  familiar  with  a  few  facts  regarding  the  nervous  system. 
The  name  nervous  system  includes  all  the  structures  in  the 
body  that  are  made  of  nerve  tissue.  For  purposes  of  study 
the  nervous  system  is  arbitrarily  divided  into  the  central  ner- 
vous system,  and  the  sympathetic  system.  The  central  nervous 
system  consists  of  the  brain,  the  spinal  cord,  and  their  nerves. 
The  sympathetic  system  consists  of  masses  of  nerve  cell-bodies 
called  ganglia,  and  the  nerves  connected  with  "them.  These 
two  systems  differ  slightly  in  function,  but  are  intimately  con- 
nected and  are  really  interdependent.  Most  of  the  nerves  that 
are  connected  with  the  skeletal  muscles  belong  to  the  central 
nervous  system,  but  the  majority  of  those  supplying  the  visceral 
muscles  belong  to  the  sympathetic  system.  Nerves  that  carry 
impulses  from  the  periphery  (in  this  connection  the  muscles)  to 
the  brain,  spinal  cord  or  ganglia,  are  called  afferent.  Nerves  that 
carry  impulses  to  the  periphery  from  the  brain,  spinal  cord  or  gang- 
lia, are  called  efferent.  Afferent  nerves  that  are  connected  with 
muscle  fibres  are  spoken  of  as  sensory.  Efferent  nerves  that  end 
in  muscle  fibres  are  spoken  of  as  motor.  For  the  purposes  of  this 
chapter,  each  of  the  terms  in  these  pairs,  i.e.  motor  and  efferent, 
sensory  and  afferent,  may  be  considered  interchangeable.  It  should 
be  remembered,  however,  that  the  terms  efferent  and  afferent  are 
applied  to  other  types  of  nerves  besides  motor  and  sensory  nerves.^ 

Differences  in,  and  results  of,  contraction.  —  Skeletal  muscle 
is  essentially  a  quick-acting  tissue.  It  contracts  quickly  and  re- 
laxes promptly.  Even  prolonged  contractions  are  compounded 
of  successive  twitches  that  follow  each  other  too  rapidly  to  permit 
of  relaxation.  In  sharp  contrast  to  this  the  contractions  of  vis- 
ceral muscle  develop  slowly,  are  maintained  for  some  time,  and 
fade  out  slowly.  In  addition  to  the  contractions  that  are  the 
result  of  stimulation  from  the  nerves,  visceral  and  cardiac  tissue 
are  also  automatic.  This  means  that  there  is  a  tendency  to  rhyth- 
mic contraction  and  relaxation  inherent  in  the  tissue  itself. 

Contractions  of  all  kinds  of  muscular  tissue  cause  a  chemical 
change  in  the  substance  of  the  muscle  fibre.     The  complex  sub- 

'  For  a  more  detailed  description,  see  Chap.  XIX. 


94  ANATOMY  FOR  NURSES  [Chap.  VII 

stances  of  which  it  is  composed  are  split  and  oxidized  into  simpler 
substances,  i.e.  water,  carbon  dioxide,  and  sarcolactic  acid.  At 
the  same  time  heat  is  generated,  energy  is  set  free,  and  various 
waste  products  are  formed.  Heat  is  a  familiar  result  of  muscular 
exercise.  The  liberation  of  energy  enables  the  muscle  to  do  its 
required  work.  The  waste  compounds  must  be  eliminated,  and, 
except  in  cases  of  prolonged  contractions,  the  system  is  able  to  get 
rid  of  thep  readily.  Prolonged  contractions  result  in  fatigue,  and 
this  means  two  things :  (1)  an  accumulation  of  waste  substances, 
known  as  fatigue  poisons,  (2)  a  loss  of  nutrient  material.  A 
period  of  rest  furnishes  opportunity  for  these  poisons  to  be  carried 
to  the  excretory  organs  by  the  blood,  and  fresh  nutritive  materials 
from  the  digestive  organs  carried  by  the  blood  to  the  muscle.  In 
cases  of  extreme  fatigue  that  are  the  result  of  prolonged  overwork 
of  a  muscle  or  muscles,  the  fatigue  poisons  have  the  same  effect 
that  the  toxins  of  tetanus  have,  and  the  over-contracted  condition 
is  spoken  of  as  tetanus  of  the  muscle.  Writer's  cramp  with  its  ac- 
companying stiffness  and  pain  is  an  example  of  this  condition. 
In  such  cases  massage  improves  the  circulation  of  the  blood  and 
IjTiiph,  thus  helping  the  elimination  of  fatigue  poisons,  and  brings 
about  a  condition  of  relaxation. 

Skeletal  Muscles.  —  The  muscles  are  separate  organs,  each 
muscle  having  its  own  sheath  of  connective  tissue,  called  epimy- 
sium.  They  vary  in  size  from  a  fraction  of  an  inch  to  nearly  twenty- 
four  inches  (600  mm.)  and  are  very  diverse  in  form.  In  the  trunk 
the  muscles  are  broad,  flattened,  and  expanded,  forming  the  walls 
of  the  cavities  which  they  enclose.  In  the  limbs  they  are  of  con- 
siderable length,  forming  more  or  less  elongated  straps.  A 
typical  muscle  is  described  as  consisting  of  a  body  and  two  ex- 
tremities. The  body  is  the  red  contracting  part,  and  the  extremi- 
ties arc  the  ends  where  they  are  attached. 

Attachment  of  the  muscles  to  the  skeleton.  —  Muscles  are  at- 
tached to  the  bones,  cartilages,  ligaments,  and  skin  in  various  ways, 
the  most  common  mode  of  attachment  being  by  means  of  tendons. 
The  muscular  fibres  converge  as  they  approach  their  tendinous 
extremities,  and  gradually  blend  with  the  fibres  of  the  tendons, 
the  tendons  in  their  turn  inserting  their  fibres  into  the  bones. 
Where  one  muscle  connects  with  another,  each  muscle  ends  in 
expanded  form  in  a  flat,  fibrous  membrane  called  aponeurosis. 


Chap.  VII] 


MUSCULAR  TISSUE 


95 


Again,  in  some  cases,  the  muscles  are  connected  with  the  bones, 
cartilages,  and  skin,  without  the  intervention  of  tendons  or 
aponeuroses. 

Origin  and  insertion.  —  It  is  customary  to  speak  of  the  attach- 
ments of  the  opposite  ends  of  muscles  under  the  names  of  origin 
and  insertion,  the  first  term  origin  being  usually  applied  to  the 
more  fixed  attachment ;  the  second  term  insertion  being  applied  to 
the  more  movable  attachment.  The  origin  is,  however,  abso- 
lutely fixed  in  only  a  very  small  number  of  muscles,  such  as  those 
of  the  face,  which  are  attached  by  one  end  to  the  bone,  and  by 
the  other  to  the  movable  skin.  In  the  greater  number,  the  muscle 
can  act  from  either  end. 

Names  of  muscles.  —  The  skeletal  muscles  are  usually  called  by 
their  Latin  names,  and  it  is  helpful  to  understand  the  meaning  of 
these  names,  as  they  are  often  descriptive  of  some  distinctive 
characteristic,  such  as  their  form,  size,  attachment,  location, 
function,  etc.^ 

The  majority  occur  in  pairs.  Only  a  few  are  single,  and  they  are 
located  about  the  median  line.  Muscles  may  be  classified  in  sev- 
eral ways.  The  most  helpful  way  is  to  classify  them  according  to 
their  location  and  function.  It  is  not  necessary  for  nurses  to  dis- 
tinguish more  than  a  few  of  the  most  prominent. 


CHIEF  MUSCLES  OF  HEAD,  FACE,  TONGUE,  AND  NECK 
Muscles  of  the  Head  —  Occipito-frontalis. 


Muscles  of  the  Face 


Muscles  of  the  Tongue 


Muscles  of  the  Neck 


Orbital  Muscles 


Muscles  of  Mastication 


Muscles  of  Expression 

I  Genioglossus. 
I  Styloglossus. 


f  Platysma. 

I  Sterno-cleido-mastoid. 


Four  recti. 

Two  oblique. 

Levator    palpebrse    su- 
perioris. 

Masseter. 

Temporal. 

Internal  pter3'goid. 

External  pterj^goid. 
r  Orbicularis  oris. 
I  Buccinator. 


1  The  student  will  find  the  Latin  derivations  and  their  meaning  in  the  Glossary 
at  the  back  of  the  book. 


96 


ANATOMY  FOR  NURSES 


[Chap.  VII 


Occipito-frontalis.  —  The  chief  muscle  of  the  liead  is  the  occi- 
pito-frontaHs,  which  may  be  considered  as  two  muscles  united  to- 
gether by  a  tliiii  aponeurosis  extending  over  and  covering  the  whole 


Fig.  67.  —  Superficial  Muscles  of  Head  and  Neck.     (Gerrish.) 


of  the  upper  part  of  the  cranium.  The  occipital  takes  its  origin 
from  the  occipital  bone  and  is  inserted  into  the  aponeurosis.  The 
frontal  takes  its  origin  from  the  tissues  in  the  region  of  the  eye- 
brows, and  is  also  inserted  into  the  aponeurosis. 

Adioti.  —  The  frontal  portion  of  this  muscle  is  the  more  po^er- 


Chap.  VII] 


MUSCULAR  TISSUE 


97 


Fig.  68.  —  Muscles  of 
Right  Eyeball  within 
THE  Orbit.  Seen  from 
the  front.  21,  superior 
rectus  ;  22,  inferior  rectus ; 
23,  external  rectus ;  24, 
internal  rectus ;  25,  su- 
perior oblique ;  26,  inferior 
oblique. 


ful ;   by  its  contraction  the  eyebrows  are  elevated,  the  skin  of  the 

forehead  thrown  into  transverse  wrinkles,  and  the  scalp  drawn 

forward.     The  occipital  acts  in  direct  line 

with  the  frontal,  and  emphasizes  its  action. 
Muscles  of  the  face.  —  There  are  about 

thirty    facial    muscles ;    they   are    chiefly 

small,  and  only  a  few  are  considered.     We 

group  them  as :    (1)  Orbital  muscles,    (2) 

jNIuscles  of  mastication,  and   (3)  Muscles 

of  expression. 

Orbital  muscles.  —  The  orbit  contains 

seven  muscles;   six  of  them  are  attached 

to  the  eyeball,  and  the  seventh  is  attached 

to  the  upper  lid.     The  six  muscles  attached 

to  the  eyeball  are  arranged  in  three  oppos- 
ing pairs. 

The  superior  and  inferior  recti.  —  These  two  muscles  have  their 

origin  at  the  apex  of  the  orbital  cavity  and  pass  straight  forward 

to  their  insertion   into   the  eyeball,   the   superior  rectus  in  the 

middle  line  above,  and  the  inferior  rectus  opposite  it  below. 
Action.  —  Contraction    of   the    superior   rectus    rolls   the   eye 

upward ;    contraction  of  the  inferior  rolls  the  eye  downward. 
The  internal  and  external  recti.  —  These  two  muscles  have  their 

origin  at  the  apex  of  the  orbital  cavity,  and  pass  forward  to  their 

insertion  into  the  eyeball,  the 
internal  on  the  inner  side,  the 
external  on  the  outer  side. 

Action. — Contraction  of  the 
internal  rectus  draws  the  eye 
inward  toward  the  nose.  Con- 
traction of  the  external  rectus 
draws  the  eye  outward. 

Superior  oblique. — The  su- 
perior oblique  muscle  arises 
from  the  apex  of  the  orbit  (the 
same  as  the  four  recti),  courses 
forward  to  the  upper  and  inner 

angle  of  the  orbit,  w^here  it  passes  through  a  loop  of  cartilage. 

Then  it  bends  at  an  acute  angle,  passes  around  the  upper  part 


Fig.  69.  —  Muscles  of  Eyeball. 
Seen  from  side.  19,  elevator  muscle  of 
eyelid ;    22-26,  same  as  in  Fig.  68. 


98 


ANATOMY  FOR  NURSES 


[ClL\P.  VII 


of  the  eyeball,  and  is  inserted  between  the  superior  and  external 
recti. 
Inferior  oblique.  —  The  inferior  oblique  arises  from  the  orbital 


Fig.  70.  —  Tempor.vl  .\nd  Deep  Muscles  about  the  Mouth.     (Gerrish.) 


plate  of  the  maxilla,  and  courses  around  the  under  portion  of  the 
eyeball  to  its  attachment  near  the  external  rectus. 

Action.  —  The  action  of  the  two  oblique  muscles  is  somewhat 
complicated,  but  their  general  tendency  is  to  roll  the  eyeball  on  its 
axis. 


Chap.  VII] 


MUSCULAR  TISSUE 


99 


In  most  cases  the  movements  of  the  eye  are  somewhat  complex 
and  more  than  one  muscle  is  involved. 

Levator  palpebrae  superioris  (lifter  of  the  upper  lid).  —  It 
arises  from  the  sphenoid  bone,  passes  forward,  and  is  inserted  into 
the  tarsal  cartilage  of  the  upper  lid. 

Action.  —  It  elevates  the  upper  lid  and  opens  the  eye. 


Fig.  71.  —  Pterygoid  Muscles.     Viewed  from  behind,  the  back  portion  of  the 
skull  having  been  removed.     (Gerrish.) 

Muscles  of  mastication.  —  They  are:  (1)  the  masseter  (chew- 
ing muscle),  (2)  the  temporal  (temple  muscle),  (3)  the  internal 
pterygoid,  and  (4)  the  external  pterygoid.  These  muscles  can 
be  located  on  the  illustrations.  They  have  their  origin  in  one  or 
more  of  the  immovable  bones  of  the  skull,  and  are  inserted  into 
the  movable  lower  jaw. 

Action.  —  The  muscles  of  mastication  generally  act  in  con- 
cert, bringing  the  lower  teeth   forcibly   into   contact  with  the 


100 


ANATOMY  FOR  NURSES 


[Chap.  VII 


upper ;  they  also  move  the  lower  jaw  forward  upon  the  upper, 
and  in  every  direction  necessary  to  the  process  of  grinding  the 
food. 

Muscles  of  expression.  —  These  muscles  are  sometimes  called 
mind  muscles  from  the  indications  that  they  afford  of  the  mental 
state  of  the  individual.  They  are  closely  connected  with  the 
under  surface  of  the  skin  or  with  each  other,  and  therefore  their 
slightest  contraction  is  shown  on  the  face.  They  include  the 
muscles  of  the  forehead,  eyelids,  nose,  and  all  those  related  to 


STYLOID    PROCESS 


ORIGIN    OF 
BTYLOMVOID 


-MANOIBLC 


Fig.  72.  —  Muscles  of  the  Tongue.     Viewed  from  the  right  side.     (Gerrish.) 


the  orifice  of  the  mouth.  We  shall  only  consider  two  important 
muscles  related  to  the  orifice  of  the  mouth. 

Orbicularis  oris.  —  The  ring  muscle  surrounds  the  opening  of 
the  mouth,  extending  from  the  nose  above  to  the  chin  below. 
It  forms  a  great  part  of  the  bulk  of  the  lips,  and  constitutes 
a  sphincter  to  the  mouth.  It  is  attached  above  to  the  partition 
between  the  nostrils  and  the  upper  jaw  bones,  and  below  to  the 
mandible. 

Action.  —  It  closes  the  mouth. 

Buccinator  (trumpeter's  muscle).  —  This  muscle  arises  from  the 
alveolar  processes  of  the  maxilla  and  mandible.     Its  different  parts 


Chap.  VII]  MUSCULAR  TISSUE  101 

converge  to  the  angle  of  the  mouth,  and  are  inserted  into  the 
orbicularis  oris. 

Action.  —  It  compresses  the  cheeks,  helps  to  close  the  mouth, 
and  assists  in  such  motions  as  blowing  a  trumpet. 

Chief  muscles  of  the  tongue.  —  The  chief  muscles  connecting 
the  tongue  and  hyoid  bone  to  the  lower  jaw  are  the  genioglossus 
and  the  styloglossus, 

Genioglossus.  —  The  genioglossus  has  its  origin  in  the  front  part 
of  the  mandible,  and  is  inserted  in  the  whole  length  of  the  tongue 
in  and  at  the  side  of  the  mid  line. 

Actioii.  — ■  It  thrusts  the  tongue  forward,  retracts  it,  and  also 
depresses  it. 

Styloglossus.  —  The  styloglossus  has  its  origin  in  the  styloid 
process  ^  of  the  temporal  bone,  and  is  inserted  in  the  whole  length 
of  the  side  and  under  part  of  the  tongue. 

Action.  —  It  draws  the  tongue  backward. 

These  muscles  are  interesting  to  us  from  the  fact  that  during 
general  anaesthesia  they,  together  with  the  other  muscles,  become 
relaxed,  and  it  is  necessary  to  press  the  angle  of  the  lower  jaw 
upward  and  forward  in  order  to  prevent  the  tongue  from  falling 
backward  and  obstructing  the  larynx. 

Muscles  of  the  neck.  —  The  two  superficial  muscles  of  the 
neck  are:    (1)  platysma,  (2)  sterno-cleido-mastoid. 

Platysma  (broad  sheet  muscle) .  —  It  arises  from  the  skin  and 
areolar  tissue  covering  the  pectoral,  deltoid,  and  trapezius  muscles, 
and  is  inserted  in  the  mandible  and  muscles  about  the  angle  of 
the  mouth. 

Action.  —  It  draws  the  angle  of  the  mouth  down  and  contracts 
the  skin  of  the  neck. 

Sterno-cleido-mastoid.  —  The  most  prominent  muscle  of  the 
neck  is  the  sterno-cleido-mastoid.  It  is  named  from  its  origin 
and  insertion,  arising  from  part  of  the  sternum  and  clavicle,  and 
being  inserted  into  the  mastoid  portion  of  the  temporal  bone. 
This  muscle  is  easily  recognized  in  thin  persons  by  its  forming  a 
cord-like  prominence  obliquely  situated  along  each  side  of  the  neck. 

Action.  —  Both  sterno-cleido-mastoid  muscles  acting  together 
flex  the  head  on  the  chest  or  neck.  They  serve  as  convenient 
landmarks  in  locating  the  great  vessels  carrying  the  blood  to  and 

1  See  Fig.  27. 


102 


ANATOIVIY  FOR  NURSES 


[Chap.  VII 


from  the  liead.  If  one  of  these  muscles  be  either  abnormally  con- 
tracted or  paralyzed,  we  get  the  deformity  called  Torticollis  or 
wrv  neck. 


CHIEF  MUSCLES  OF  THE  TRUNK 

They  may  be  arranjjjed  in  four  groups :  — 

_    .         [  Trapezius. 
1.  Muscles  of   the  Back        ' 


2.  Muscles  of  the  Chest 


3.  Muscles  of  the  Thorax 


4.  Muscles  of  the  Abdomen 


Latissimus  dorsi. 
I  Pcctoralis  major. 
I  Pectoralis  minor. 

I  External  intcrcostals. 
Internal  intcrcostals. 
Levatores  costarum. 
External  oblique. 
Internal  oblique. 
Rectus  abdominis. 
Transvcrsalis. 


OCCIPITAL    BONE 


Muscles  of  the  back.  —  The  muscles  of  the  back  are  disposed  in 
five  layers,  one  beneath  another.     The  two  largest  and  most  su- 
perficial muscles  are:    (1)  the 
trapezius,     (2)    the   latissimus 
dorsi. 

Trapezius.  —  The  trapezius, 
so  called  because  right  and 
left  together  make  a  large  dia- 
mond-shaped sheet,  arises  from 
the  middle  of  the  occipital 
bone,  from  all  the  cervical  and 
all  the  thoracic  vertebrae.  The 
connection  with  the  cervical 
\'ertebr<T  is  through  the  me- 
dium of  the  ligamentuni  nuchoB, 
which  is  a  form  of  ligament 
that  stretches  from  the  protu- 
berance of  the  occiput  to  the 
spinous  processes  of  the  seven 
cervical   vertebrse.     (See   Fig. 

^     „„      ^       ^  ^,  73.)     From  this  extended  line 

Fig.   73.  —  The    Lio.wientum    Nucil*:. 

Seen  from  the  right  side.     (Gerrish.)  of    origin    the    fibres    converge 


r 


Chap.  VII] 


MUSCULAR  TISSUE 


103 


-OCCIPITALIS 


LAST 

CERVICAL  " 
VERTEBRA 


I 

.#^ 


i\ 


/ 


rLATISSIMUS 


to  their  insertion  in  the  clavicle,  the  acromion  process,  and 
the  spine  of  the  scapula.  It  is  a  very  large  muscle,  and  cov- 
ers the  other  muscles  of  the  upper  part  of  the  back  and  neck, 
also  the  upper  portion  of  the  latissimus  dorsi. 

Action.  —  It  lifts   the  

shoulder  and  rotates  the  ^ 

angle  of  the  scapula  back-  -  If  M         ^ 

ward.  /    '        ,r 

Latissimus  dorsi. —  /  '/ 

The  latissimus  dorsi 
arises  from  the  last  six 
thoracic  vertebree,  and 
through  the  medium  of 
the  lumbar  aponeurosis, 
from  the  lumbar  and 
sacral  part  of  the  spine 
and  from  the  crest  of 
the  ilium.  It  covers  the 
lower  part  of  the  back. 
The  fibres  pass  upward 
and  converge  into  a 
thick,  narrow  band, 
which  winds  around  and 
finally  terminates  in  a 
flat  tendon,  which  is  in- 
serted into  the  front  of 
the  humerus  just  below 
its  head. 

Action.  —  It  draws  the  humerus  backward,  the  body  forward, 
and  keeps  the  scapula  close  to  the  chest,  as  in  using  crutches  or 
climbing.  If  the  arm  is  elevated,  it  draws  it  down,  back,  and 
rotates  it  in,  as  in  swimming. 

Muscles  of  the  chest.  —  The  chief  bulk  of  the  anterior  mus- 
cular wall  of  the  chest  is  made  up  of  the  pectoral  muscles. 

Pectoralis  major.  —  The  pectoralis  major  arises  from  the  sternal 
end  of  the  clavicle,  the  sternum,  and  the  six  upper  ribs.  The  fibres 
converging  form  a  thick  mass,  which  is  inserted  by  a  tendon  of 
considerable  breadth  into  the  upper  part  of  the  humerus. 

Action.  —  It   draws  the  arm  downward  and  forward. 


Fig.  74. 


Muscles  in  the  Superficial  Later 
OF  THE  Back.      (Gerrish.) 


104 


ANATOMY   FOR   NURSES  [Chap.  MI 


Fig.  75.  —  Front  of  Chest  .\nd  Shoulder  of  Right  Side,  Superficial 
Muscles.     (Gerrish.) 


INTERNAL 

INTERCOSTAL 

SEEN  THROUGH 

ARTIFICIAL  GAP 

IN  EXTERNAL 


Fig.  76.  —  Intercostal  Muscles  in  Right  Wall  of  Thorax.     (Gerrish.) 


Chap.  VII]  MUSCULAR   TISSUE  105 

Pectoralis  minor.  —  The  pectoralis  minor  is  underneath  and 
entirely  covered  by  the  major.  It  arises  from  the  surface  of  the 
third,  fourth,  and  fifth  ribs,  near  the  cartilages,  and  is  inserted  in 
the  coracoid^  process  of  the  scapula. 

Action.  —  It  pulls  the  shoulder  downward  and  assists  in  the 
elevation  of  the  ribs  during  inspiration. 

Muscles  of  the  thorax.  —  The  muscles  of  the  thorax  are  chiefly 
concerned  with  the  movements  of  the  ribs  during  respiration. 
They  are  the:    (1)  intercostals,  and  (2)  levatores  costarum. 

Intercostals.  — The  intercostals  are  found  filling  the  spaces  be- 
tween the  ribs.  Each  muscle  consists  of  two  layers,  one  ex- 
ternal and  one  internal,  and  as  there  are  eleven  intercostal  spaces 
on  each  side,  and  two  muscles  in  each  space,  it  follows  there 
are  forty-four  intercostal  muscles.  The  fibres  of  these  muscles 
run  in  opposite  directions. 

External  intercostals.  —  The  external  fibres  arise  from  the  lower 
border  of  a  rib,  run  downward,  forward,  and  inward,  and  are  in- 
serted into  the  upper  border  of  the  next  lower  rib. 

Action.  —  They  pull  the  ribs  upward  and  outward,  thereby  in- 
creasing the  chest  cavity. 

Internal  intercostals.  —  The  internal  fibres  arise  from  the  lower 
border  of  a  rib,  run  downward,  outward,  and  backward,  and  are 
inserted  into  the  upper  border  of  the  next  lower  rib. 

Action.  —  They  depress  the  ribs. 

Levatores  costarum  (lifters  of  the  ribs).  —  They  arise  from  the 
transverse  processes  of  the  vertebrae  from  the  seventh  cervical  to 
the  eleventh  thoracic,  and  are  inserted  into  the  outer  surface  of 
the  ribs  between  the  tubercles  and  angles. 

Action.  —  They  assist  in  elevation  of  the  first  ten  ribs,  and  with 
other  muscles  draw  the  lower  ribs  backward. 

Diaphragm.  —  The  diaphragm  is  a  thin,  musculo-fibrous  par- 
tition placed  obliquely  between  the  abdominal  and  thoracic 
cavities.  It  is  dome-shaped,  and  consists  of  muscle  fibres  arising 
from  the  whole  of  the  internal  circumference  of  the  thorax,  and 
of  a  central  aponeurotic  tendon,  shaped  somewhat  like  a  trefoil 
leaf,  into  which  the  muscle  fibres  are  inserted.  It  has  three  large 
openings  for  the  passage  of  the  aorta,  the  large  artery  of  the  body, 
the  inferior  vena  cava,  one  of  the  largest  veins  of  the  body,  and  the 

1  See  Fig.  49  for  eoracoid  process  of  scapula. 


106 


ANATOMY  FOR  NURSES 


[Chap.  VII 


oesophagus,  or  gullet ;  it  has  also  some  smaller  openings  for  the 
passage  of  blood-vessels,  nerves,  etc.  The  upper  or  thoracic  sur- 
face of  the  diaphragm  is  highly  arched ;  the  heart  is  supported  by 
the  central  tendinous  portion  of  the  arch,  the  right  and  left  lungs 
by  the  lateral  portions,  the  right  portion  of  the  arch  being  slightly 
higher  than  the  left.     The  lower  or  under  surface  of  the  diaphragm 


t||^\\  >^\' 


'^fK 


\  a! 


\   y 


Fig.  77.  —  Di.\phrag.m.     Viewed  from  in  front.      (Gerrish.) 

is  deeply  concave,  and  covers  the  liver,  stomach,  pancreas,  spleen, 
and  kidneys. 

Action.  —  The  diaphragm  is  probably  the  most  important 
voluntary  muscle  in  the  body,  as  well  as  the  chief  respiratory 
and  expulsive  muscle.  In  the  act  of  inspiration  the  diaphragm 
contracts,  and  in  contracting  flattens  out  and  descends,  the  ab- 
dominal viscera  are  pressed  downwards,  and  the  thorax  is  ex- 
panded vertically.  In  forcible  acts  of  expiration,  and  in  efforts  of 
expulsion  from  the  thoracic  and  abdominal  cavities,  the  diaphragm 
and  all  the  other  muscles  which  tend  to  depress  the  ribs,  and  those 
which  compress  the  abdominal  cavity,  concur  in  powerful  action 
to  empty  the  lungs,  to  fix  the  trunk,  and  to  expel  the  contents  of 


Chap.  VII] 


MUSCULAR  TISSUE 


107 


the  abdominal  viscera.  Thus  it  follows  that  the  action  of  the 
diaphragm  is  of  assistance  in  expelling  the  foetus  from  the  uterus, 
the  fseces  from  the  rectum,  the  urine  from  the  bladder,  and  its 
contents  from  the  stomach  in  vomiting. 

Muscles  of  the  abdomen.  —  The 
chief  muscles  of  the  abdomen  are :  (1) 
external  oblique,  (2)  internal  oblique, 
(3)  rectus  abdominis,  and  (4)  trans- 
versalis. 

External  oblique.  —  The  strongest 
and  most  superficial  of  the  abdominal 
muscles  is  the  external  oblique.  It 
arises  from  the  outer  surface  of  the 
eight  lower  ribs.  The  fibres  incline 
downward  and  forward  and  terminate 
in  the  broad  aponeurosis,  which,  meet- 
ing its  fellow  of  the  opposite  side  in  the 
linea  alba,  covers  the  whole  of  the  front 
of  the  abdomen.  The  lowest  fibres  of 
the  aponeurosis  are  gathered  together 
in  the  shape  of  a  thickened  band,  which 
extends  from  the  anterior  superior  spi- 
nous process  of  the  ilium  to  the  pubic 
bone,  and  forms  the  well-known  and 
important  landmark,  the  inguinal  liga- 
ment, more  commonly  known  as  Pou- 
part's  ligament  from  the  anatomist 
who  first  described  it. 

Internal  oblique.  —  The  internal  oblique  muscle  lies  just  beneath 
the  external  oblique.  It  arises  from  the  inguinal  ligament,  the 
outer  crest  of  the  ilium,  and  slightly  from  the  lumbar  fascia.^ 

'  The  lumbar  fascia  springs  from  the  vertebral  column  in  three  layers  :  — 

(1)  Outer,  or  posterior. 

(2)  Middle. 

(3)  Inner,  or  anterior. 

(1)  The  outer  layer  begins  at  the  spinous  process  of  the  lumbar  and  sacral 
vertebrae.  It  is  attached  above  to  the  last  rib,  and  below  to  the  outer  tip  of  the 
iliac  crest  and  the  ilio-lumbar  ligament. 

(2)  The  middle  layer  starts  from  the  transverse  processes  of  the  lumbar  vertebrse 

(3)  The  inner  layer  starts  from  the  front  of  the  bases  of  the  same  processes. 
The  fascia  resulting  from  the  combination  of  these  three  layers  gives  rise  to  the 

internal  oblique  and  transversalis  muscles. 


Fig.  7S.  —  Rectus  Abdomi- 
nis AXD  Obliquds  Internus 
OF  Right  Side.     (Gerrish.) 


108 


ANATOMY   FOR   NURSES 


[Chap.  VII 


Its  most  posterior  fibres  run  upward  and  forward  and  are 
inserted  in  the  costal  cartilages  of  the  four  lower  ribs.  At  the 
outer  border  of  the  rectus  muscle  the  remaining  muscle  fibres 
expand  into  a  ijroad  aponeurosis.  This  aponeurosis  divides  into 
two  layers,  one  passing  before,  the  other  behind,  the  rectus 
muscle;  they  reunite  at  its  inner  border  in  the  linea  alba,  and 
thus  form  a  sheath  for  the  rectus,  extending  from  the  xiphoid 
process  to  the  crest  of  the  pubes.  At  the  lower  part  of  the  rectus 
the  posterior  layer  of  the  aponeurosis  is  deficient. 

Rectus  abdominis.  —  The  rectus  is  a  long,  flat  muscle,  consisting 
of  vertical  fii)res  situated  at  the  fore  part  of  the  abdomen,  and 

enclosed  in  the  fibrous  sheath  formed 
by  the  aponeurosis  of  the  internal  ob- 
lique. It  arises  from  the  pubic  bone, 
and  is  inserted  into  the  cartilages  of 
the  fifth,  sixth,  and  seventh  ribs ;  it  is 
separated  from  the  muscle  of  the  other 
side  by  a  narrow  interval  which  is 
occupied  by  the  linea  alba. 

Transversalis.  —  The  transversalis 
muscle  lies  beneath  the  internal  oblique. 
The  fibres  arise  from  the  six  lower  costal 
cartilages,  the  lumbar  fascia,  the  crest 
of  the  ilium,  and  the  outer  third  of  the 
inguinal  ligament.  The  greater  part  of 
its  fibres  have  a  horizontal  direction, 
and  are  inserted  in  the  linea  alba  and 
the  crest  of  the  pubes. 

Linea  alba.  — The  linea  alba,  or  white 
line,  is  a  tendinous  band  formed  by  the 
union  of  the  aponeuroses  of  the  two 
oblique  and  transverse  muscles,  the 
tendinous  fibres  crossing  one  another 
from  side  to  side.  It  extends  perpen- 
dicularly, in  the  middle  line,  from  the 
xiphoid  portion  of  the  sternum  to  the 
pubes.  It  is  a  little  broader  above  than  below,  and  a  little  be- 
low the  middle  it  is  widened  into  a  flat,  circular  space,  in  the 
centre  of  which  is  situated  the  umbilicus. 


Fig.  79.  —  Transversalis 
Abdominis  of  Right  Side. 
(Gerrish.) 


Chap.  VII]  MUSCULAR  TISSUE  109 

Action  of  the  abdominal  muscles. — When  these  muscles  con- 
tract, they  compress  the  abdominal  viscera,  and  constrict  the 
cavity  of  the  abdomen,  in  which  action  they  are  much  assisted  by 
the  descent  of  the  diaphragm.  By  these  means  they  give  assist- 
ance in  parturition,  defecation,  micturition,  and  vomiting.  They 
also  assist  in  respiration,  and  in  various  movements,  such  as 
climbing,  flexing  the  thorax  upon  the  pelvis,  rotation  of  the 
trunk,  etc. 

The  inguinal  canal.  —  Between  the  abdominal  muscles,  parallel 
to,  and  about  one-half  inch  above  the  inguinal  ligament,  is  a  tiny 
canal,  about  one  and  one-half  inches  long,  called  the  inguinal  canal. 
The  internal  opening  of  the  canal  is  called  the  internal  abdominal 
ring,  and  is  situated  in  the  fascia  of  the  transversalis  muscle,  mid- 
way between  the  spine  of  the  ilium  and  the  crest  of  the  pubic  bone. 
The  canal  ends  in  the  external  abdominal  ring,  which  is  in  the  tendon 
of  the  external  oblique  muscle.  This  canal  transmits  the  sper- 
matic cord  in  the  male,  or  the  round  ligament  of  the  uterus  in 
the  female. 

Weak  places  in  the  abdominal  walls.  —  The  internal  and  ex- 
ternal abdominal  rings,  described  above,  the  umbilicus,  and  an- 
other ring  situated  just  below  the  inguinal  ligament,  and  called  the 
femoral  ring,  are  considered  weak  places  because  they  are  so  often 
the  seat  of  hernia.  Hernia,  ^  or  rupture,  is  a  protrusion  of  a  portion 
of  the  contents  of  a  body  cavity,  and  in  this  instance  would  mean 
a  protrusion  of  a  portion  of  the  intestine  or  mesentery  through  one 
of  these  weak  places.  If  it  occurs  in  the  umbilicus,  it  is  called 
umbilical  hernia;  in  the  inguinal  rings,  inguinal  hernia;  and  in  the 
femoral  ring,  femoral  hernia.  The  inguinal  canal  is  larger  in  the 
male  than  in  the  female,  hence  inguinal  hernia  is  more  common 
in  the  male  than  in  the  female. 

MUSCLES  OF  THE  UPPER  EXTREMITIES 

A  certain  number  of  muscles  situated  superficially  on  the  trunk 
are  frequently  grouped  with  the  muscles  of  the  upper  extremities, 
as  their  function  is  to  attach  the  upper  limbs  to  the  trunk  and 
move  the   shoulders   and  arms.     Of  these,   the  two   superficial 

•  If  the  skull  is  injured  so  that  a  portion  of  the  brain  protrudes,  it  would  also  be 
correctly  spoken  of  as  hernia  of  the  brain.  Of  course  this  is  more  unusual  than 
abdominal  hernia. 


110 


ANATOMY  FOR   NURSES 


[Chap.  VII 


muscles  we  have  mentioned  as  covering  the  back,  the  trapezius  and 
latissimus  dorsi,  and  the  pectoral  muscles  covering  the  front  of  the 
chest,  are  the  chief. 

The  muscles  of  the  extremities  are  arranged  in  antagonistic 
groups,  the  action  of  one  group  opposing  the  action  of  the  other. 
The  movements  of  which  the  extremities  are  capable  are  flexion 
and  extension,  abduction  and  adduction,  supination  and  prona- 
tion, circumduction  and  rotation.     (See  page  87.) 

Functionally  we  might  group  the  muscles  of  the  upper  extremi- 
ties as  follows. 


Name  of  Muscle 

Location 

Function 

Trapezius 

Upper  portion  of  back 

Moves  shoulder 
upward  and 
backward. 

Pectoralis  minor 

Chest,  under  pectoralis 

Moves  shoulder 

Moving  the 

major 

downward 

Shoulder 

and  assists  in 
the  elevation 
of  the  ribs 
during  in- 
spiration. 

[  Deltoid 

Covers  the  top  of  the 

Abduction. 

Moving  the 
Arm 

Pectoralis  major 

shoulder 
Chest,  from  sternum  to 

Adduction. 

humerus 

Latissimus  dorsi 

Lower  portion  of  back 

Adduction. 

Biceps 

Anterior  surface  of  arm 

Flexion. 

Triceps 

Posterior  surface  of  arm 

Extension. 

Moving  the 

Pronators 

Anterior      surface      of 

Pronation. 

Forearm 

forearm 

Supinators 

Posterior     surface     of 
forearm 

Supination. 

Deltoid.  —  The  deltoid  is  a  coarse,  triangular  muscle  covering 
the  top  of  the  shoulder.  It  arises  from  the  clavicle,  acromion 
process,  and  spine  of  the  scapula,  extends  downw^ard,  and  is 
inserted  into  the  middle  of  the  shaft  of  the  humerus,  on  the  outer 
side.     (See  Fig.  81.) 

Action.  —  It  abducts  —  raises  the  arm  from  the  side  so  as  to 
bring  it  at  right  angles  to  the  trunk.     This  action  is  opposed 


Chap.  VII] 


MUSCULAR   TISSUE 


111 


by  the  pectoralis  major  and  latissimus  dorsi,  which  have  been 
described. 

Biceps.  —  The  biceps  is  a  long  fusiform  muscle,  occupying  the 
whole  of  the  anterior  surface  of  the  arm ;  it  is  divided  above 
into  two  portions  or  heads,  from  which  circumstance  it  has  re- 


FiG.  80.  —  Muscles  of  the 
Front  op  the  Right  Shoulder 
AND  Arm.     (Gerrish.) 


Fig.   81.  —  Muscles    on    the    Dorsum    of    the 
Right  Shoulder  and  Arm.     CGerrish.) 


ceived  its  name.  It  arises  by  these  two  heads  from  the  scapula, 
and  is  inserted  into  the  radius. 

Action.  —  It  flexes  the  forearm  on  the  arm. 

Triceps.  —  The  triceps  is  situated  on  the  back  of  the  arm, 
extending  the  whole  length  of  the  posterior  surface  of  the  humerus. 
It  is  of  large  size,  and  divided  above  into  three  heads ;  hence  its 
name.  Two  of  the  heads  have  their  origin  in  the  scapula  and  one 
in  the  humerus.  The  three  heads  unite  in  a  common  tendon 
which  is  inserted  into  the  ulna. 


112 


ANATOMY  FOR  NURSES 


[C  HAl'.  VII 


Action.  —  It  is  the  great  exten- 
sor musele  of  the  forearm,  and  is 
tlie  direct  antagonist  of  the  l)ieeps. 

Muscles  of  the  forearm.  —  The 
muscles  covering  the  forearm  are 
disposed  in  groups,  the  pronators 
and  flexors  being  placed  on  the 
front  and  inner  part  of  the  fore- 
arm, and  the  supinators  and  ex- 
tensors on  the  outer  side  and  back 
of  the  forearm :  they  antagonize 
one  another.  The  pronators  turn 
the  palm  of  the  hand  backward 
and,  when  the  elbow  is  flexed, 
downward  or  prone.  The  supi- 
nators turn  the  palm  of  the  hand 
forward,  and,  when  the  elbow  is 
flexed,  upward  or  into  the  supine 
position.  The  flexors  and  exten- 
sors have  long  tendons,  some  of 
which  are  inserted  into  the  bones 
of  the  wrist,  and  some  into  the 
bones  of  the  fingers :  they  serve 
to  flex  and  extend  the  wrist  and 
fingers. 

MUSCLES   OF    THE   LOWER 
EXTREMITIES 

If  we  compare  the  muscles  of 
the  shoulder,  arm,  and  forearm 
with  those  of  the  hip,  thigh,  and 
leg,  we  shall  see  that  the  anterior 
muscles  of  the  former  correspond 
roughly  with  the  posterior  muscles 
of  the  latter,  the  muscles  of  the 

Fig.    82.  — 

Muscles  in  hip,  thigh,  and  leg,  however,  be- 
of?h?rTght  i"g  larger  and  coarser  in  texture 
Forearm  AND  than  those  of  the  shoulder,  arm, 

Hand.    (Ger- 

rish.)  and  forearm. 


Chap.  VII] 


MUSCULAR  TISSUE 


113 


Functionally  we  might  group  the  most  important  muscles  of  the 
lower  extremities  as  follows :  — 


Name  of  Muscle 


Moving 

the      ^ 
Thigh 


Moving 
the 

Leg 


Moving 
the 
Foot 


Psoas  magnus 
Iliacus 

Gluteus  maximus 


Gluteus  medius 

Gluteus  minimus 

Adductor  magnus 
Adductor  longus 
Adductor  brevis 
Adductor  gracilis 

Sartorius 


Biceps 

Semitendinosus 

Semimembranosus 

Rectus  femoris 
Vastus  externus 
Vastus  internus 
Vastus  intermedius 

Tibialis  anterior 
Peroneus  tertius 

Tibialis  posterior 

Gastrocnemius 

Soleus 

Peroneus  longus  ■ 
Peroneus  brevis 


Location 


I  In    the    pelvis    and 
I      upper  part  of  thigh 

Region  of  buttocks 


Under  gluteus  maxi- 
mus 
Under  gluteus  medius 


•i  Mesial  part  of  thigh 
Mesial  part  of  thigh 


Function 


Front  of  thigh 


§  Back  of  thigh 


■^  Front  of  thigh 

& 


Front  of  leg 


\  Back  of  leg 


Outer  part  of  leg 


Flexion  and  out- 
ward rotation 

Extension,  out- 
ward rotation 
and  adduc- 
tion. 

Abduction  and 
inward  rota- 
tion. 

Addud,  rotate 
and  flex  thigh. 

Adducts  thigh 
and  flexes  the 
leg. 

Flexes  leg,  helps 
in  rotation 
and  abduc- 
tion of  thigh. 

Flexors  of  knee, 
rotate  leg  in- 
ward, extend 
thigh. 

Extension  of 
leg,  flexes  the 
thigh. 


Flexors. 


Extensors. 


Psoas  magnus.  —  The  great  loin  muscle  arises  from  the  last 
thoracic  and  all  the  lumbar  vertebrae  with  the  included  inter- 


114 


ANATOMY   FOR   NURSES 


[Chap.  VII 


vertebral  cartilages.  It  extends  down  and  forward,  then  down 
and  backward,  to  its  insertion  in  the  small  trochanter  of  the 
femur. 

Iliacus.  —  This  mnsele  and  its  relation  to  the  psoas  magnus  is 
well  shown  in  Fig.  83.     It  arises  from  the  iliac  fossa  and  is  inserted 


Fig.  83.  —  P.so.\s,  Iliacus,  and  Obturator  Externus  Muscles.     (Gerri.sh.) 

partly  into  the  tendon  of  the  psoas  and  partly  into  the  small 
trochanter  of  the  femur. 

Action.  —  The  psoas  magnus  and  iliacus  act  as  one  muscle  to 
flex  the  thigh  on  the  pelvis,  and  rotate  the  femur  outward. 

Glutei  muscles.  —  The  three  gluteal  muscles  are  coarse  in  tex- 
ture, and  form  the  chief  prominence  of  the  buttocks. 


Chap.  VII] 


MUSCULAR  TISSUE 


115 


Gluteus  maximus  arises  from  the  ilium,  sacrum,  and  coccyx, 
and  is  inserted  into  the  great  trochanter  of  the  femur. 

Action.  —  It  is  a  powerful  extensor  of  the  hip-joint.  It  also 
rotates  the  femur  outward,  and  adducts  the  thigh. 

Gluteus  medius  and  gluteus  minimus  are  under  the  gluteus 
maximus  and  almost  entirely  covered  by  it.  They  arise  from  the 
outer  surface  of  the  ilium  and  are  inserted  into  the  great  trochanter. 

Action.  —  Abduction  of  the  thigh,  and  when  the  thigh  is  flexed, 
inward  rotation. 

Adductors.  —  The  four  adductor  muscles  are  called  respectively 
magnus  (great),  longus  (long),  brevis  (short),  and  gracilis  (slender). 
They  are  situated  on  the  inner 
side  of  the  thigh.  They  arise 
from  different  portions  of  the 
pubic  bone,  and  the  first  three 
are  inserted  into  the  inner  side 
of  the  femur.  The  gracilis  is 
inserted  into  the  shaft  of  the 
tibia. 

Action.  —  The  magnus,  lon- 
gus, and  brevis  adduct,  rotate, 
and  flex  the  thigh.  The  gra- 
cilis adducts  the  thigh  and 
flexes  the  leg. 

Sartorius.  —  The  sartorius, 
or  tailor's  muscle,  is  a  long,  rib- 
bon-like muscle  situated  on  the 
front  of  the  thigh.  It  crosses 
the  thigh  obliquely  from  its 
origin  in  the  ilium  to  its  insertion  in  the  tibia.  It  was  formerly 
supposed  to  be  the  muscle  principally  concerned  in  producing  the 
posture  assumed  by  the  tailor  in  sitting  cross-legged,  hence  its  name. 

Action.  —  It  flexes  the  leg,  and  helps  in  rotation  and  abduction 
of  the  thigh. 

Biceps.  —  The  biceps  arises  by  two  heads,  one  from  the  ischium, 
and  the  other  from  the  posterior  surface  of  the  femur.  It  is  in- 
serted into  the  head  of  the  fibula  and  the  outer  tubercle  of  the  tibia. 

Semitendinosus  and  Semimembranosus.  —  They  arise  from 
the  ischium,  and  are  inserted  into  the    upper  and  inner  part 


Fig.  84. 


Gluteus  Maximus  of  Right 
Side.      (Gerrish.) 


116 


ANATOMY   FOR  NURSES 


[Chap.  VII 


of  the  tibia.  These  three  muscles,  the  biceps,  semitendino- 
sus,  and  semimembranosus,  cover  the  back  of  the  thigh,  hence 
are  named  jiostrrior  femoral,  or  hamstring  muscles. 


Fig.  85.  —  Mcscles  in  thb 
Dorsum  of  the  Right  Thigh. 
(Gerrish.) 


Fig.  86.  —  Supekficial  Muscles 
IN  Front  Part  of  the  Right  Thigh. 
(Gerrish.) 


Action.  —  They  flex  the  knee,  rotate  the  leg  inward,  and  extend 
the  thif^'h. 

Quadriceps.  —  The  quadriceps  is  a  four-headed  muscle  that 
covers  the  front  of  the  thigh,  and  is  analogous  to  the  triceps  cover- 


Chap.  VII] 


MUSCULAR  TISSUE 


Fig.  87. — Vastus  Intermedius 
OP  Right  Side.     (Gerrish.) 

ing  the  back  of  the  arm.  Each  head 
is  described  as  a  separate  muscle  :  (1) 
rectus  femoris,  (2)  vastus  externus, 
(3)  vastus  internus,  (4)  vastus  inter- 
medius. 

The  rectus  femoris  arises  from  the 
ilium,  the  other  three  arise  from  the 
femur.  They  pass  downward,  and 
are  inserted  by  one  tendon  to  the 
tubercle  of  the  tibia.  The  tendon 
passes  in  front  of  the  knee-joint,  and 
the  patella  is  a  sesamoid  bone  devel- 
oped in  it. 

Action.  —  The  quadriceps  is  the 
great  extensor  of  the  leg;  it  also 
flexes  the  thigh,  and  antagonizes  the 
action  of  the  hamstring  muscles. 


U< 


Fig.    88.  —  Gastrocnemius    of 
Right  Side.     (Gerrish.) 


118  ANATOMY  FOR   NURSES  [Chap.  VII 

Gastrocnemius  and  soleus.  —  The  gastrocnemius  and  soleus 
form  the  calf  of  the  leg.  The  gastrocnemius  arises  by  two  heads 
from  the  two  condyles  of  the  femur.  The  soleus  is  in  front  of  the 
gastrocnemius.  It  arises  from  the  tibia  and  fibula.  The  direction 
of  both  is  downward,  and  they  are  inserted  into  a  common  tendon, 
the  tendon  of  the  heel  (tendo  Achillis),  which  is  the  thickest  and 
strongest  tendon  in  the  body,  and  is  inserted  into  the  calcaneum, 
or  heel  bone. 

Action.  —  Extension  of  the  foot,  and  when  the  ankle  joint  is 
fixed,  extension  of  the  leg.  These  muscles  possess  considerable 
power,  and  are  constantly  called  into  use  in  standing,  walking, 
dancing,  and  leaping ;  hence  the  large  size  they  usually  present.^ 

Fasciae.  —  As  previously  stated  (page  37)  most  of  the  muscles 
are  closely  covered  by  sheets  of  fibrous  tissue  called  fascife.  These 
fasciae  not  only  envelop  and  bind  down  the  muscles,  but  also  sep- 
arate them  into  groups.  Such  groups  are  named  according  to 
the  parts  of  the  body  where  they  are  found,  viz. :  cervical 
fascia,  thoracic  fascia,  abdominal  fascia,  pelvic  fascia,  etc.  In- 
dividual fascia  are  frequently  given  the  name  of  the  muscle  which 
they  envelop  and  bind  down,  viz. :  temporal  fascia,  pectoral 
fascia,  deltoid  fascia,  etc.  It  is  important  for  the  student  to 
realize  the  continuity  of  the  fibrous  membranes.  Tendons,  liga- 
ments, and  fasciae  blend  with  periosteum,  tendons  and  fasciae 
serve  as  ligaments,  tendons  lose  themselves  in  fasciae,  and  tendons 
of  some  muscles  serve  as  fasciae  for  others. 

Annular  ligaments.  —  In  the  vicinity  of  the  wrist  and  ankle, 
parts  of  the  deep  fascia  become  blended  into  tight  transverse 
bands,  which  serve  to  hold  the  tendons  close  to  the  bones.  These 
bands  are  called  annular  ligaments.     (See  Fig.  82.) 

'  Additional  muscles  included  in  Summary. 


Chap.  VII] 


SUMMARY 


119 


Muscular 
Tissue    1 


SUMMARY 

r  Cells  develop  into  fibres. 
'  Intercellular  substance  at  a  minimum. 
Connective  tissue  —  supporting  framework. 


Classification 


Striated 


/  Voluntary 
\  Skeletal 


Non-     f  Involuntary 
striated  I  Visceral 


tern. 


10 


11 


1.  Marked  with  transverse  strise. 

2.  Under  control  of  wiU. 

3.  Attached  to  bones. 

4.  Composed  of  bundles  of  fibres. 

5.  Fibres  are  multinuclear  elon- 

gated cells. 

6.  Connective  tissue  framework. 

7.  Outer   sheath   of   connective 

tissue  —  Epimysium. 

8.  Well  supplied  with  f  Sensory. 

nerves.  I  Motor. 

9.  Majority   of  nerves   connect 

with  central  nervous  sys- 
f  Brain. 
I  Spinal  cord. 
Well  supplied  \vith  blood- 
vessels and  lymphatics. 
Contracts  quickly,  relaxes 
promptly. 

1.  Not  marked  with  transverse 

striae. 

2.  Not  under  control  of  will. 

3.  Found    in    walls    of    blood- 

vessels and  viscera. 

4.  Composed  of  bundles  of  fibre- 

cells. 

5.  Fibre-cells   contain   just   one 

nucleus. 

6.  Connective  tissue  framework. 

7.  Outer   sheath   of   connective 

tissue  —  Epimysium. 

8.  Well  supphcd  with  i  Sensory. 

nerves.  I  Motor. 

9.  Majority  of  nerves   connect 

with   sympathetic   nervous 
system. 

10.  Well    supplied    with    blood- 

vessels and  lymphatics. 

11.  Contracts  slowly  and  continu- 

ously for  long  periods  of  time. 

12.  Possesses  inherent  power  of 

automatic  contraction. 


120 


ANATOMY   FOR   NURSES 


[Chap.  VII 


Classification  < 


r  Striated 
Cardiac  <  Involuntary 
I  Visceral 


y^ 


Stimxili 


Characteristics 


Contraction 


Fatigue 


Skeletal 
Muscles 


1.  Striated  but  not  distinctly. 

2.  Not  under  control  of  will. 

3.  Made  of  square  bundles  of 
fibres. 

4.  Fibres  are  elongated  cells, 
contain  just  one  nucleus,  no 
sarcolenuna. 

5.  Fine  fibrils  from  cells  form  a 
network. 

6.  Connective  tissue  framework. 

7.  Contracts  and  relaxes  quickly 
and  unceasingly  during  life. 

Term  used  to  describe  influences  which  irritate  or  stimu- 
late. 

1.  Chemical. 

2.  Mechanical. 
Varieties                   \  3.  Thermal. 

4.  Electrical. 

5.  Nervous  —  important  one. 

1.  Irritabihty  —  response  to  a  stiumlus. 

2.  Contractility  —  muscle  becomes  shorter  and  thicker. 

3.  Extensibility  —  muscle  can  be  stretched. 

4.  Elasticity  —  muscle  readily  returns  to  original  shape. 

5.  Tonicity  —  mild,  sustained  contraction. 

„,      .    ,  ^,  /  Fibres  shorten. 

Physical  Change  (  pi^res  thicken. 

'  Take  up  oxj'gen. 

r  Carbon  dioxide. 
Formation  of  I  Sarcolactic  acid. 

i  Various  otherwastes. 
Heat  is  liberated. 
,  Energy  is  set  free. 

Accumulation  of  waste  poisons. 
Loss  of  nutritive  material. 

/  Origin  —  more  fixed  attachment. 

1  Insertion  —  more  movable  attachment. 


Chemical  Change " 


Chap.  VII] 


SUMMARY 


121 


ta 


03 


o 


^-^ 


W 


03 


o 


-3   03  o 


I — I  -Lj  ^-r 


T3 

d 

03 


>, 


=3 


d 

S3 


-^3 


Q       °^-i 


"T^      •    c3 


p^    p^       p^ 


3   o3'm'3   o 


-3  P  a; 
P^ 


!  fe  d 

>  C  o 
!   O    ^ 

■^^ 

d  vi 

c3    O 
d    O 


o3  tH 

^  > 

.     3  O 

tU             C3  •— a 

d  t»  ^  »2 

03   Q^    C  P 

d  2  c  > 


S      O      O      O      g 


a        ^     ^ 


o3 ,    o3 ,    oj 

d  ^     d  ^  .g 


O) 


0 


d;=l  d 

dj  :3  oj  :r3 

d  ^  d  3 

o  M  oi> 

<1     <1 


-^    OJ  -73    OJ    c    03 

c3    O    c3    O    >>  2^ 
•      :-    !-,    c    "^    ^ 

S..2  I.2I 
P     k:;     S 


CL> 


O    03 


d  iu 

CD    X 
^    CU 

o-t3 

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I    03 


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o  .s 


r-H       O.rt—H       !_  curd 

03  -ri   -fJ    03  ~^    diTTi 

-?,  Sg-^'^pad 


rTJ 


d  cs 


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d 

o3 


d 

o3 


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d 

c3 


d 
o 


a 


"^     "S     "S 
000 


O      H 


o 

X 


a 
<1 


a 
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o 

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X 

a 

<1 


o3 


a 
<! 


d 
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a 

CO 


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bC  d   d 


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03 


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a  a 
!/3      cc 


^ 

T) 

en 

3 

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n> 

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a 

is 

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j3 

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d 

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ifi 

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d 

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cr 

a 

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0 

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at 

ss 


122 


ANATOMY  FOR  NURSES 


IChap.  VII 


I 


a 


b    CO 

J  o  o 


c  o-^ 


m 


1^  "^  S 


U 


o:   o  -1^  •-< 

O     O     CO    0? 

f-  -—  -^  t^ 

r-    -.   3   " 
C    O   fc,    « 

c  -^  !B.  ^ 


c3 


1^   = 
g   O   G 

o  o  _2 


q=l   c 


O    O 


c3 


^    O 


CO 

1^ 


^  o  o 


c3  ;? 


O  cS 

■53 

-►->  o 

c3  CO 

T3  +3 

fr^  O 

o  ^ 


o 


J5  o 


^  =:  <  CD 

5, 


o^.  js 


« 


u;:;—  ^ 


o 


-7-    O         _0 


13 
C 
c3 


3   O 
bCo 


^      ^      -^  ^  S 


o 


2  (=-=  2  S 


c3 


bO 
G 


3  " 


m   O 


o  o 

S  ^ 

o"5. 


^-^ 


3 
J3 


p 


CO 

O 

=  J 

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•43   ai 


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o   C  c! 

fc-    C  O 

03:7:  a 

>  s  o 


"2  '^ 
'S,  o 
>>a 

CO 


o-:3 


c3    ^    "5 

---       Coo 


rt  > 


CO    S 
3 


cor; 
02 


k!  o   >   c3       -r;   c3 
j::  C  t,  -        c?x; 

—  -JJ   i)        -»-' 


a: 


"t:      3     o        ^ 

O        22       O  72 


"2 
'o 


-ii 

e 


c3 


JU    M 


H 


0) 

0 

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4> 

ca 

H 

3 

0 

Ig 

O  JU 


s*^. 


Chap.  VII] 


SUMMARY 


123 


-73    o 


-a 

§°         -^ 

d 

^     r-         .     C 

|> 

^    O    C    03 

rH 

c:  •-  o 

a 
o 

o 

nil 

-M 

rj 

a 

;h 

-3   o   C   -^ 

3 

c3 
03 

§^   bC^ 

^ 

-=5  -•=•£: 

-C! 

03 

<u    CC  _^    0)       . 

is 

^ 

^.I^^-H 

O 

Pulls 
ass 
rib 

Pull 
wa 

H- 1 

CO  ;3   I> 
tC   Go 

-^-^   - 


>i     .25 


^a 


g  ^  o  a 
cc  'n  'C 


Q    <: 


o         o 

.2  ^' 
„        :=!  o 

p  ■"     .2 

'^  rj  'm 

•^  Tj  'T   ?3 
-<  o^  o 


V.2 


St3  fl 

2-S  o 

f-i     C3    C3 

S   o   03 

03  _C  ^ 


vis- 
and 
vis. 

i.i 

03 

S 
o 

^  o 

X  o 

gT3 

T) 

omi 
e   ri 
nth 

s-a 

XJ 

OS 

^  o 

T3-G    O 

03 

X!*"  a 

03  "^ 

^ 

o3           =3 

the 

esses 
hest 

O 

"  2 

tH    03 
5R    ^  03 

o 

^-^^ 

O     Oj 

o3    CO 

03           r/) 

CO     " 

-.    q; 

ompr 
cera, 
flcxe 

CO  rr 

O      tH 

0  " 

U 

p 

u 

a 


.  _,  CO    M 

X  -C  _Q    03 

O  O  •!-■  "o 

o3  o3  ^•^    lh 

03  03  03     O) 

<+-!  t*-!  ->^   ^ 

o  o  ^  3 

tn  S-,  '^     03 

03  03  03     H 

tH  ^    S  JD  .03  t:  -T-, 


-l^    CB    03 

^.  p  a 


Is 


cj^    o3  03 

S    £3    O)    03^ 


^     03  t., 

03    ^  03 

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a—'  &■ 


!=1   bC 

03     fl 

,0   03 


O)  ^j  -*^ 

a  d,  o 
,  ^  o 


3  O 

o 

o  fi 

to  «-' 
03 

bC  ~ 


^■^03-^ 


<<      O 


03    ^ 


«  '^  S    C! 

r^  t-  03      *3 

d  03  «     03 

"S  03  So 


II 

13  a 


O 


13  o> 

o3  a 

3    CO 


M    03 

bC 
03    o    ;-( 


t3 
CO 


;::^^ 


o 


CO    _, 
03 '^ 

CO   o3 


O 


9^  SrS  g  ^ 

^      Oj      G 

3    03     g3 


03 


03 


CO   ^; ' 
> 


OJ    CO  -g    > 


C    03    > 


O 
03  ^ 


03 

S  S    ° 

Z3  o3 

b  2    03    5S 


^   S   bjO 


03  ^ 

03    O— 1 
bO        03 

CO   ^^ 

03  -^ 

_,  o 

^     tH     r-T  03  X! 

•-<  03  c  t; 

C    ='  —  "*-    3 
I— I  Ah 


,X  -"-d  A 


ci 

^    ^ 

t4_, 

c3    3 

C5 

C/J 

O 

C 

o 

3 

hf 

X 

— <    C 

•^ 

'"^ 

CO 

;-H 

CO"-!^ 

o3 

O^ 

bC  p 

3 

O 

3 
bO 

s 


Ah 


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3 

rr 

a 

42 

o 

bU 

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03 

ni 

^ 

& 

03 

n 

-tJ 

X 

« 

W 

:3 

o 

c 


_2  ^ 


P^ 


124 


ANATOMY  FOR   NURSES 


[Chap.  VII 


g 

o 

o3 

V.-I 

i 

«4-l 

3             ^ 

o          a. 

l 

G^ 

1 

C5      • 

TS 

-d 

§         -    . 

M 

3 
o3 

a 
o 

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a 

s 

M 

o  a 
a^ 

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rt 

CD 
CO 

03 

o 
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o 

o 

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, 

c 
o 

% 

o 

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3 

<J 

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pli 

S          H 

s     s 

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3   =3         2 

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X. 

3 
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0 

o 

a 

c» 

g'a    2 
^^    ° 

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3               2 
3^        "S 

l-H 

ll 

3 

•-3 

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m       p^ 

^3        ci  c:- 

rH    t^    O    O^  :^ 

o  o  S  ^  S 

• 

to 

3 

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, 

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vm 

13 

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73 

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C3 

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o3 

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03 

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00                    05 

CO               00 

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cc    rt    c3   cc 

3   t-i 

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K 

1— ( 

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3 
03 

a 

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C^ 

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t< 

0)   ^   o 

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t-  .3   i-i 

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Chap.  VII] 


SUMMARY 


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ANATOMY  FOR  NURSES 


[Chap.  VII 


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CHAPTER    VIII 

SPECIAL   MEMBRANES   AND    GLANDS 
MEMBRANE 

The  word  "  membrane  "  in  its  widest  sense  is  used  to  designate 
any  thin  expansion  of  tissue.  Thus  we  speak  of  the  periosteum 
as  a  fibrous  membrane ;  and  the  layer  of  cells  beneath  the  epi- 
thelium of  free  surfaces  is  called  a  basement  membrane.  In  a 
restricted,  although  the  commonest  sense,  the  word  "  membrane  " 
is  used  to  denote  an  enveloping  or  a  lining  tissue  of  the  body. 

Classification  of  membranes.  —  The  chief  membranes  of  the 
body  are  classified  as  follows  :  — 

1.  Serous. 

2.  Synovial. 

3.  Mucous. 

4.  Cutaneous. 

SEROUS   MEMBRANES 

Serous  membranes  are  thin,  transparent,  tolerably  strong,  and 
elastic.  The  surfaces  are  moistened  by  a  fluid  resembling  serum, 
from  which  the  membranes  obtain  their  name  of  serous  mem- 
branes. They  consist  of  two  layers  only:  (1)  endothelium, 
(2)  corium. 

(1)  Endothelium  is  the  name  given  to  a  variety  of  epithelium 
found  lining  {i.e.  lying  within)  certain  parts  of  the  body.  It 
consists  of  a  single  layer  of  flattened  transparent  cells  joined 
edge  to  edge  so  as  to  form  a  smooth  membrane. 

(2)  The  corium  consists  of  a  thin  layer  of  fibrous  tissue,  and  con- 
tains blood-vessels,  lymph-vessels,  and  lymphoid  tissue. 

Serous  membranes  are  attached  to  the  underlying  parts  by 
areolar  tissue,  called  "  subserous  "  tissue.  They  are  found  lining 
closed  cavities  and  passages  that  do  not  communicate  with  the 
exterior.     They  may  be  divided  into  three  classes  :  — 

127 


128  ANATOMY  FOR   NURSES  [Chap.  VIII 

(1) .  Serous  membranes  proper. 

(2)  The  lining  membrane  of  the  vascular  system. 

(3)  The  liniiiij  inc'nii)rane  of  certain  cavities. 

(1)  Serous  membranes  proper. — With  one  exception,  these 
membranes  form  closed  sacs,  one  part  of  which  is  attached  to  the 
walls  of  the  cavity  which  it  lines,  —  the  parietal  portion,  —  whilst 
the  other  is  reflected  over  the  surface  of  the  organ  or  organs  con- 
tained in  the  cavity,  and  is  named  the  visceral  portion  of  the  mem- 
brane. In  this  way  the  viscera  are  not  contained  within  the  sac, 
but  are  really  placed  outside  of  it,  and  some  of  the  organs  may 
receive  a  complete,  while  others  receive  only  a  partial,  or  scanty, 
investment. 

This  class  of  serous  membranes  includes :  — 

(a)    The  two  pleurw,  which  cover  the  lungs  and  line  the  chest. 

(6)  The  pericardium,  which  covers  the  heart,  and  lines  the  outer 
jfibrous  pericardium. 

(c)  The  peritoneum,^  which  lines  the  abdominal  cavity,  clothes 
its  contained  viscera,  and  also  the  upper  surface  of  some  of  the 
pelvic  viscera. 

(2)  The  lining  membrane  of  the  vascular  system.  —  This  applies 
to  the  internal  coat  of  the  heart,  blood-vessels,  and  Ij-mphatics. 
It  bears  a  close  resemblance  to  the  proper  serous  membranes  in 
structure  and  appearance. 

(3)  The  lining  membrane  of  certain  cavities  :  — 

(a)  One  illustration  of  this  is  the  capsule  of  Tenon.  This 
capsule  is  a  shut  sac  placed  back  of  the  eyeball,  with  a  visceral 
layer  upon  the  globe  of  the  eye,  and  the  parietal  layer  next  to  the 
bed  of  fat  on  which  the  eyeball  rests. 

(6)  The  brain  and  spinal  cord  enclose  cavities  which  are  lined  with 
a  delicate  serous  membrane.  One  of  the  membranes  that  envelop 
the  brain  and  spinal  cord  (arachnoid)  is  also  a  serous  membrane. 

Function  of  serous  membranes.  —  The  most  important  function 
of  serous  membrane  is  protection,  which  is  accomplished  in  two 
ways :  (1)  by  forming  a  smooth,  slippery  lining  or  covering  for  the 
viscera,  blood-vessels,  and  cavities  with  which  it  is  associated,  and 

1  The  peritoneum  in  the  female  is  the  one  exception  to  the  rule  that  serous  mem- 
branes are  perfectly  closed  sacs,  as  it  has  two  openings  by  which  the  Fallopian 
(uterine)  tubes  communicate  with  its  ca\nty. 


Chap.  VIII]     SPECIAL  MEMBRANES  AND   GLANDS     129 

(2)  by  secreting  serum  which  acts  as  a  lubricating  fluid  and  tends 
to  lessen  friction. 

The  inner  surface  of  a  serous  membrane  is  free,  smooth,  and 
polished ;  and  in  the  case  of  serous  membranes  proper,  the  inner 
surface  of  one  part  is  applied  to  the  corresponding  inner  surface  of 
some  other  part,  only  a  very  small  quantity  of  fluid  being  interposed 
between  the  surfaces.  The  organs  situated  in  a  cavity  lined  by  a 
serous  membrane,  being  themselves  also  covered  by  it,  can  thus 
glide  easily  against  its  walls  or  upon  each  other,  their  motions  being 
rendered  smoother  by  the  lubricating  fluid. 

SYNOVIAL  MEMBRANES 

Synovial  membranes  are  frequently  classed  as  serous  membranes, 
because  their  function  is  the  same  and  they  have  no  communica- 
tion with  the  surface  of  the  body.  They  differ,  however,  (1)  in 
the  nature  of  their  secretion,  (2)  in  their  structure,  and  (3)  they  are 
associated  with  the  bones  and  muscles,  and  not  with  the  viscera. 
Synovial  membrane  is  composed  of  fibrous  tissue  which  has  on  its 
free  surface  an  imperfect  covering  of  cells  that  are  irregularly 
shaped,  and  secrete  a  viscid  glairy  fluid  that  resembles  the  white  of 
egg,  and  is  named  synovia. 

They  are  divided  into  the  following  classes  :  — 

1.  Articular. 

2.  Vaginal. 

3.  Bursal. 

1 .  Articular.  —  Articular  synovial  membranes  are  found  sur- 
rounding and  lubricating  the  cavities  of  the  movable  joints  in 
which  the  opposed  surfaces  glide  on  each  other. 

2.  Vaginal.  —  Vaginal  synovial  membranes  are  found  forming 
sheaths  for  the  tendons  of  some  of  the  joints,  and  thus  facilitating 
their  motion  as  they  glide  in  the  fibrous  sheaths  which  bind  them 
down  against  the  bones. 

3.  Bursal.  —  Bursal  synovial  membranes,  or  synovial  bursae, 
are  found  in  the  form  of  simple  sacs,  interposed,  so  as  to  prevent 
friction,  between  two  surfaces  w^hich  move  upon  each  other. 
These  bursse  may  be  either  deep-seated,  or  subcutaneous.  The 
deep-seated  are  for  the  most  part  placed  between  a  muscle  and  a 
bone,    or   between   a   tendon    and   a   bone.     The   subcutaneous 


130 


ANATOxMY  FOR  NURSES 


[Chap.  VIII 


bursae  lie  immediately  under  the  skin,  and  occur  in  various  parts 
of  the  body,  interposed  between  the  skin  and  some  firm  promi- 
nence beneath  it.  The  large  bursa,  situated  over  the  patella, 
is  a  well-known  example  of  this  class,  but  similar,  though  smaller, 
bursa?  are  found  also  over  the  olecranon,  the 
malleoli,  the  knuckles,  and  other  prominent 
parts. 

Function  of  synovial  membranes.  —  As 
previously  stated,  the  function  of  synovial 
membranes  is  similar  to  that  of  serous 
membranes,  but  synovial  membranes  are 
associated  with  the  bones  and  muscles. 


MUCOUS  MEMBRANES 

The  mucous  membranes,  unlike  the  se- 
rous membranes,  line  passages  and  cavities 
which  communicate  with  the  exterior. 
Their  surface  is  coated  over  and  protected 
by  mucus,  from  which  it  derives  its  name. 
The  mucous  membranes  of  different  parts 
are  continuous,  and  they  may  nearly  all  be 
reduced  to  two  great  divisions ;  namely, 
(1)  gastro-pulmonary,  and  (2)  the  genito- 
urinarv. 


k 


i\\ 


J 


Fig.  «9.  —  The  An- 
terior Annular  Liga- 
ment OF  THE  Ankle 
AND  the  Synovial  Mem- 
branes OF  the  Tendons 
BENEATH  IT.  Artifuially 
distended.      (Gcriish.) 


(1)  Gastro-pulmonary. —  The  gastro-pul- 
monary mucous  membrane  covers  the  inside 
of  the  alimentary  canal,  the  air-passages, 
and  the  cavities  communicating  with  them. 
It  commences  at  the  edges  of  the  lips  and 
nostrils,  proceeds  through  mouth  and  nose 
to  the  throat,  and  thence  is  continued  throughout  the  entire  length 
of  the  alimentary  canal  to  the  anus.  At  its  origin  and  termina- 
tion it  is  continuous  with  the  external  skin.  It  also  ex-tends 
throughout  the  trachea,  bronchial  tubes,  and  air-sacs.  From  the 
interior  of  the  nose  the  membrane  may  be  said  to  be  prolonged 
into  the  frontal,  ethmoidal,  sphenoidal,  and  maxillary  sinuses, 
also  into  the  lacrimal  passages,  and  under  the  name  of  conjunc- 
tival membrane,  over  the  fore  part  of  the  eyeball  and  inside  of 
the  eyelids,  on  the  edges  of  which  it  again  meets  with  the  skin. 


Chap.  VIII]     SPECIAL   MEMBRANES  AND   GLANDS     131 


From  the  upper  and  back 
part  of  the  pharynx  a  pro- 
longation extends  on  each 
side,  along  the  passage 
to  the  ear,  —  Eustachian 
tube,^  —  and  offsets  in  the 
ahmentary  canal  go  to  Hne 
the  saHvary,  pancreatic, 
and  biHary  ducts,  and  the 
gall-bladder. 

(2)  Genito-urinary.  — 
The  genito-urinary  mucous 
membrane  line^  the  inside 
of  the  bladder,  and  the 
whole  urinary  tract  from 
the  interior  of  the  kidneys 
to  the  meatus  urinarius,  or 
orifice  of  the  urethra ;  it 
also  lines  the  vagina, 
uterus,  and  Fallopian 
(uterine)  tubes  in  the  fe- 
males. A  study  of  Figs. 
91  and  92  will  make  this 
plain. 

Structure.  —  A  mucous 
membrane  is  composed  of 
a  layer  of  connective  tissue 
called  the  corium,  which 
is  bounded  toward  the  free 
surface  by  a  basement 
membrane  and  covered  by 
a  layer  of  epithelium.  Be- 
neath the  corium  we  usu- 
ally find  a  thin  layer  of 
muscular  tissue  called  the 
muscularis  mucosae.  From 
the  above,  it  will  be  seen 

1  Named  after  Eustaehius,  a 
famous  anatomist. 


FRONTAL 
SINUSES 
0UCT8  OF 
LACHRYMAL GLANnS 
UPPER  LIDS 
EY[ 
LOWER  LIDS 

TEAR  DUCTS 


.ETHMOIDAL  SINUSES 


.SPHENOIDAL 
SINUSES 

,MAXILLAR¥ 

SINUSES 


^MIDDLE  EARS 
I  MASTOID 
CAVITIES 
EUSTACHIAN  TUBEJ 


Fig.  90.  —  Dia- 
gram OF  THE  GaSTRO- 
PULMONARY  MuCOUS 

Membrane,  show- 
ing THE  Continuity 
OF  ALL  ITS  Parts. 
(Gerrish.) 


132 


ANATOMY  FOR  NURSES 


[Chap.  VIII 


that,  starting  at  the  free  surface,  the  order  of  the  tissues  is  as 
follows :  — 

(1)  Epithelium. 

(2)  Basement  membrane. 

(3)  Corium. 

(4)  Muscularis  mucosae. 

(1)  The  epithelium  is  the  most  constant  part  of  a  mucous 
membrane,  being  continued  over  certain  regions  to  which  the 
other  parts  of  the  membrane  cannot  be  traced.     It  may  be  scaly 


Fig.  91. 


Diagram    of   the    Female    Genito-urinary    Mucous    Membrane, 
SHOWING  Continuity  of  all  its  P.\rts.     (Gerrish.) 


and  stratified,  as  in  the  throat,  columnar,  as  in  the  intestine,  or 
ciliated,  as  in  the  respiratory  tract. 

(2)  The  basement  membrane  consists  of  a  layer  of  flattened 
cells,  and  is  really  j)art  of  the  corium. 

(3)  The  corium  of  a  mucous  membrane  is  composed  of  either 
areolar  or  hinphoid  connective  tissue.  It  is  generally  much 
thicker  than  in  serous  or  synovial  membranes,  and  varies  much 
in  structure  in  different  parts. 

(4)  The  muscularis  mucosae  consists,  as  previously  stated, 
of  a  thin  layer  of  muscular  tissue. 

The  mucous  membranes  are  attached  to  the  parts  beneath  them 
by  areolar  tissue,  here  named  "  submucous,"  and  which  differs 
greatly  in  quantity  as  well  as  in  consistency  in  different  parts. 
The  connection  is  in  some  cases  close  and  firm,  as  in  the  cavity 


Chap.  VIII]     SPECIAL  MEMBRANES  AND   GLANDS     133 


of  the  nose.  In  other  instances,  especially  in  cavities  subject  to 
frequent  variations  in  capacity,  like  the  oesophagus  and  the  stomach, 
it  is  lax;  and  when  the  cavity  is  narrowed  by  contraction  of  its 
outer  coats,  the  mucous  membrane  is  thrown  into  folds,  or  rugae, 
which  disappear  again  when  the  cavity  is  distended.  But  in 
certain  parts  the  mucous  membrane  forms  permanent  folds  that 
cannot  be  effaced,  and  which  project  conspicuously  into  the  cavity 
which  it  lines.  The  best-marked  example  of  these  folds  is  seen 
in  the  small  intestine, 
where  they  are  called 
valvulce  conniventes^  (cir- 
cular folds),  and  which 
are  doubtless  provided 
for  increasing  the 
amount  of  absorbing 
surface  for  the  products 
of  digestion.  In  some 
locations  the  free  surface 
of  mucous  membrane 
contains  minute  glands, 
or  it  is  covered  with 
papillse,  villi,  or  cilia. 

PapillcB. —  The  papilhe 
are    best    seen    on    the       _  _  ,,        ^ 

Fig.    92.  —  Diagram    of  the    Male    Genito- 
tongue ;     they  are   small     urinary  Mucous    Membrane    showing    Conti- 
e  J.1  •  NuiTY  of  all  its  Parts.     (Gerrish.) 

processes  or  the  conum,  ^ 

mostly  of  a  conical  shape,  containing  blood-vessels  and  nerves, 

and  covered  with  epithelium. 

Villi.  —  The  villi  are  most  fully  developed  on  the  mucous  coat 
of  the  small  intestine.  They  are  little  projections  of  the  mucous 
membrane,  covered  with  epithelium,  containing  blood-vessels  and 
lacteals,  and  are  favorably  arranged  for  absorbing  nutritive 
matters  from  the  intestines. 

Cilia.  —  For  description  of  cilia  see  page  28. 

Function  of  mucous  membranes.  —  The  function  of  mucous 
membranes  is  (1)  protection,  (2)  support  of  blood-vessels  and 
lymphatics,  (3)  to  furnish  a  large  amount  of  surface  for  absorption. 

(1)   It   protects    by    forming  a  lining   or  inside    skin  for    all 

'  See  page  266. 


134 


ANATOMY   FOR   NURSES 


[Chap.  VIII 


the  passages  that  communicate  with  the  exterior.  These 
jxissages  are  subject  to  the  contact  of  foreign  substances,  which 
are  introduced  into  the  body,  and  waste  materials,  which  are 
expelled  from  the  body.  The  mucus  which  it  secretes  is  a  thicker 
and  more  sticky  fluid  than  either  serum  or  synovia,  and  by  coating 
the  surface  lessens  the  possibility  of  irritation  from  food,  waste 
materials,  or  secreted  substances.  The  cilia  of  the  respiratory 
tract  also  assist  in  the  function  of  protection. 
They  keep  up  an  incessant  motion,  and  thus 
carry  mucus  toward  the  outlet  of  these  pas- 
sages. Dust  and  foreign  materials  usually 
become  entangled  in  the  mucus  and  are 
forced  out  with  it. 

(2)  The  redness  of  mucous  membranes  is 
due  to  their  abundant  supply  of  blood.     The 
small   blood-vessels  which  convey  blood   to 
the  mucous  membranes  divide   in  the  sub- 
mucous tissue,   and   send    smaller  branches 
into  the  corium,  where  they  form  a  network 
of  capillaries  just  under  the  basement  mem- 
brane.    The  lymphatics  also  form  networks 
in  the  corium,  and  communicate  with  larger 
Fig.  93.  —  An  Jntes-    vessels  in  the  submucous  tissue  below. 
:r,^nI;'''^Tpith'::iir;        (3)  The   modifications  of    mucous    mem- 
b,  h,  capillary  network ;    brane,  such  as  the  valvulre  conniventes,  pa- 

d,  lacteal  vessel.  .  ,  ,      .,,.  i  i      i>         i  i> 

piUfe,  and  villi,  are  largely  tor  the  purpose  ot 
increasing  the  surface  for  absorption,  and  also  to  enable  it  to 
carry  more  blood-vessels  and  lymphatics. 

CUTANEOUS  MEMBRANE 

By  this  term  is  indicated  the  membrane  which  covers  the  body 
and  is  commonly  spoken  of  as  skin.  It  is  a  complex  structure, 
iind  has  several  functions  in  addition  to  serving  as  a  protective 
covering  for  the  deeper  tissues  lying  beneath  it.  It  will  be  more 
fully  considered  in  Chapter  XVIII. 


GLANDS 

A  gland  is  a  secreting  organ,  or  an  organ  which  abstracts  from  the 
blood  certain  materials  and  makes  of  them  a  new  substance. 


Chap.  VIII]     SPECIAL  MEMBRANES   AND   GLANDS     135 

The  simplest  form  of  a  gland  may  consist  of  just  one  cell,  such 
as  the  goblet  cells/  or  may  be  a  mere  depression  on  the  surface  of 
a  membrane,  or  a  complex  organ  like  the  liver.  No  matter 
what  the  size  or  shape  may  be,  all  glands  have  three  essential 
characteristics:  (1)  epithelial  cells  which  are  the  active  secreting 
agents,  (2)  a  liberal  blood  supply  from  which  the  material  for  the 
secretion  is  drawn,  (3)  they  are  under  the  direct  control  of  the  ner- 
vous system  and  secretion  is  their  response  to  stimulation,  just  as 
contraction  is  the  response  of  a  muscle.  The  usual  arrangement  is 
for  the  cells  to  cover  the  free  surface  of  a  basement  membrane, 
a  dense  network  of  capillaries  to  be  spread  upon  its  under  surface, 
and   nerve   fibrils   to  form  a  network  in  contact  with  the  cells. 


Fig.  94. — Dl^gram  showing  De\t;lopment  of  Glands:  A,  a  mere  dimple  in 
the  surface  ;  B,  enlargement  by  division  ;  C,  enlargement  by  dilatation  ;  D,  a  combi- 
nation of  B  and  C ;  E,  a.  raeemosp  gland ;  F,  development  of  method  oi  E ;  G,  & 
single  tube  intricately  coiled.      (Gerrish.) 

In  order  to  economize  space  and  to  provide  a  more  extensive 
secreting  surface,  the  membrane  is  generally  increased  by  dipping 
down  and  forming  variously  shaped  recesses. 

Classification.  —  The   secreting  glands   are  of  three  kinds  :  — 

1.  Simple. 

2.  Compound. 

3.  Ductless. 

L  Simple  glands.  —  The  simple  glands  are  generally  tubular  or 
saccular  cavities,  which  open  upon  the  surface  by  a  single  duct. 
They  are  named  simple  tubular,  or  saccular  glands.  Sometimes 
the  tube  is  so  long  that  it  coils  upon  itself,  as  in  the  sweat  glands 
of  the  skin.     These  are  named  simple  convoluted  tubular  glands. 

2.  Compound  glands.  —  In  the  compound  glands  the  cavities 
are  subdivided  into  smaller  tubular  or  saccular  cavities,  opening 

>  See  page  267. 


136  ANATOMY  FOR  NURSES  [Chap.  Mil 

by  small  ducts  into  the  main  duct,  which  pours  the  secretion 
upon  the  surface.  If  composed  of  many  tubes,  either  straight  or 
convoluted,  they  are  called  compound  tubular  glands;  if  composed 
of  gr()Uj)s  of  small  sacs,  they  are  called  racemose  glands. 

3.  Ductless  glands.  —  This  term  is  applied  to  a  collection  of 
glandular  structures  that  possess  no  ducts.  Whatever  secretion 
or  excretion  they  produce  is  discharged  into  the  blood,  either 
directly  or  indirectly  by  way  of  the  lymphatics. 

SECRETION 

A  new  substance,  the  product  of  a  gland,  elaborated  from 
the  blood  by  cell  action,  and  intended  for  use  in  the  body  is  called 
a  secretion. 

For  purposes  of  study  we  may  divide  the  secretions  into  two 
groups :  — 

(1)  External  secretions. 

(2)  Internal  secretions. 

External  secretions.  —  This  term  is  used  to  designate  those 
secretions  of  glandular  tissues  which  are  carried  to  their  destina- 
tion by  a  duct.  All  of  the  digestive  juices  —  saliva,  gastric  juice, 
pancreatic  juice,  bile,  and  intestinal  juice  —  are  examples  of  ex- 
ternal secretions,  because  thej'  are  carried  off  from  the  respective 
glands  in  which  they  are  formed  by  means  of  ducts. 

Function.  —  The  function  of  the  external  secretions  is  dealt  with 
in  connection  with  the  organs  which  produce  them. 

Internal  secretions.  —  This  term  is  used  to  designate  those 
secretions  of  glandular  tissues  which  are  not  carried  off  to  the 
exterior  by  a  duct,  but  instead  are  discharged  into  the  blood  or 
l\Tnph.  The  conception  is  that  probably  all  the  ductless  glands 
form  secretions  which  have  a  profound  influence  on  nutritive 
changes  in  the  body.  Such  secretions  are  called  internal  secre- 
tions. It  has  also  been  shown  that  not  only  the  ductless  glands, 
but  some  at  least  of  the  typical  glands  provided  with  ducts,  may 
give  rise  to  internal  secretions.  For  example,  the  pancreas  forms 
the  pancreatic  juice  and  discharges  it  by  means  of  a  duct  into  the 
small  intestine.  In  addition,  it  is  believed  that  the  pancreas  forms 
an  internal  secretion  which  passes  into  the  blood. 

Function.  —  On  account  of  the  difficulty  of  separating  internal 


Chap.  VIII] 


SUMMARY 


137 


secretions  from  the  blood  or  lymph,  the  precise  nature  of  their 
composition  or  function  is  not  known,  beyond  the  fact  that  most 
of  them  are  essential  to  metabolism  and  they  contain  chemical 
substances  called  hormones.  The  term  hormone  is  suggestive, 
because  it  means  messenger  and  is  applied  to  a  substance  which 
is  produced  in  one  organ  and  on  being  carried  by  the  blood  to  an- 
other organ  stimulates  this  latter  to  functional  activity. 

Excretion.  —  An  excretion  resembles  a  secretion,  except  that 
whereas  the  secretion  is  intended  for  use  in  the  body,  the  excretion 
is  generally  formed  to  be  thrown  out  of  the  body.  It  therefore 
follows  that  all  excretions  are  first  secretions,  and  some  substances 
are  made  use  of  before  they  are  eliminated.  For  instance,  bile 
serves  several  purposes  before  it  is  eliminated,  so  that  it  is  first 
a  secretion  and  then  an  excretion.  Urine,  on  the  other  hand,  is 
a  secretion,  but  is  formed  only  to  be  eliminated. 


Definition  — 


Varieties 


SUMMARY 

I  Any  thin  expansion  of  tissue. 
I  An  enveloping  or  lining  tissue. 

1.  Serous  membranes. 

2.  Synovial  membranes. 

3.  Mucous  membranes. 

4.  Cutaneous  membranes. 


Consist  of 


1 .  Endothelium  —  a  single  layer  of  flat  cells. 

2.  Corium  — ■  a  thin  layer  of  fibrous  tissue. 
Found  —  lining  closed  cavities  or  passages  that  do  not  communicate 

with  the  exterior.     They  are  moistened  by  serum. 

'  Pleurae — cover  the  lungs 

and  line  the  chest. 
Pericardium  —  covers 
the  heart  and  lines  the 
outer  fibrous  pericar- 
dium. 
Peritoneum — covers  the 
abdominal    and     the 
top  of  some  of  the  pel- 
Three  Classes  {  vie  organs,  lines  the 

abdominal  cavity. 

Lining  membrane  of  the  J  r>i     j  i 

^  ,  \  Blood-vessels, 

vascular  system  I  y         ,    ,. 

•'  ">  Lymphatics. 


'  Serous  membranes  proper  - 


138 


ANATOMY  FOR  NURSES 


[Chap.  VIII 


Lining  membrane  of  cer- 
tain cavities 


Function  —  Protection  • 


Back  of  eye  —  capsule 

of  Tenon. 
Lining  membrane  of  the 
cavity  of  the  central 
nervous  system. 
Viscera. 
Vascular 
sj'^stem. 
Certain  cav- 
ities. 

Furnishes  a  secretion  —  serum  —  which 
acts  as  a  lubricant. 


1.  Furnishes  a  cover  or  lining. 


Consist  of 


[l 


Three  Classes  ■ 


Imperfect  layer  of  irregularly  shaped  cells. 

Layer  of  fibrous  tissue. 

/  ...     ,  .  ,  ,  f  Surround  cavities  of 

Articular  synovial  membranes  {  ,  ,    .  ■ 

[      movable  jonits. 

Vaginal  synovial  membranes 


for 


Bursal  synovial  membranes 


Function  —  Protection 


Furnishes  a  cover  or  lining 


Found 


Two  Divisions 


Consist  of 


J  Form    sheaths 
1      tendons. 
■  Sacs  interposed  be- 
tween   two    sur- 
faces which  move 
upon  each  other. 
Joints. 
Tendons. 
Sacs  be- 
tween 
muscles 
and  bones. 
Furnishes    a    secretion  —  synovia  —  which 
acts  as  a  lubricant. 

lining  passages  that  communicate  with  the  exterior  and  are 
protected  by  tniicus. 

Alimentary  canal. 
Air-passages. 
Gastro-pulmonary  |  Cavities    communicating    with 
both  alimentary  canal  and  air- 
passages. 
J  Urinarj'  tract. 
\  Generative  organs, 
r  Stratified. 

1.  Epithelium         {  Columnar, 
i  Cihated. 

2.  Basement  membrane,  a  layer  of  flat  cells. 
I  Areolar  tissue,  or 
I  LjTiiphoid  tissue. 


Genito-urinary 


3.  Corium 


Chap.  VIIIJ 


SUMMARY 


139 


Consist  of 


Modifications 


Function 


Definition 


Structure 


Classification 


I 


4.  Muscularis    mucosae  —  thin    layer    of    muscular 
tissue. 

Ruga.  -  temporary  folds    {  ^^^^^^^^'^ 

Valvulse  coniiiventes  —  permanent  folds  of  mucous 
membrane    found    in   small 
intestine. 
Papillae  —  conical  processes  of  mucous  membrane 
best    seen    on   tongue.      Contain    blood- 
vessels and  nerves. 
Villi  —  tiny  thread-like  projections  of  the  mucous 

membrane  of  small  intestine. 
Cilia  —  hair-like  processes. 
r  Inside  skin. 
Protection       <  Secretion  of  mucus. 

I  Action  of  cilia. 
Support  —  for  network  of  blood-vessels. 
Absorption  — •  Various    modifications    increase    the 
surface. 


Glands  are  organs  that  form  secretions. 

A  single  cell,  or  many  cells  arranged  in  various  ways. 
Epithehal  cells. 
A  Uberal  blood-supply. 
Intimate     connection   with 

nervous  system. 
Tubular  — ■  tube  shape. 
Saccular  —  sac  shape. 
Convoluted   tub  ular  —  Ion  g 
tube  coiled  upon  itself. 
f  Compound  tubular  —  many 
2.  Compound  —  wa?i?/        tubes. 

I  Racemose  —  many  sacs. 
no  duct 


\  Essentials 


1.  Simple  —  one  duct 


ducts 
3.  Ductless 


Definition  — 

the  glands 


Classification 


Secretions  are  substances  elaborated  from  the  blood  by 
They  are  intended  to  perform  some  office  in  the  body. 
External  secretions  —  are  substances  formed  by  the 
simple  and  compound  glands  and  discharged  by 
means  of  a  duct. 
Internal  secretions  —  are  substances  formed  by  any 
kind  of  gland  and  discharged  into  the  blood  or 
lymph. 
External  secretions  —  studied  later. 

f  Essential  to  metabolism. 
1  Stimulate  by  means  of  hormones. 
Excretion  —  a  secretion  which  is  ehminated. 


Function 


Internal  secretions 


140 


ANATOMY  FOR  NURSES 


[Chap.  VIII 


TABLE  OF  SECRETIONS  AND  EXCRETIONS 


Secretion 

Secreting  Organs 

Reaction 

Main  Purpose 

Mucus 

Mucous  cells  of 
mucous    mem- 
brane 

Alkaline 

Lubricant  and  diluent. 

Serous 

Serous         mem- 

Alkaline 

Lubricant  and  diluent. 

secretion 

branes 

Tears 

Lacrimal  glands 

Alka,Une 

To  moisten  the  conjunctiva. 

Saliva 

Salivary  glands 

Alkaline 

To  moisten  food  and  digest  car- 
bohydrates. 

Gastric 

Stomach 

Acid 

To  digest  proteins. 

juice 

Pancreatic 

Pancreas 

AlkaUne 

To  digest  proteins,  fats,  and 

juice 

carbohj^dratcs. 

Succus 

Intestines 

Alkaline 

To  dilute  the  chyme. 

entericus 

Bile 

Liver 

Alkaline 

Part  of  the  bile  is  used  in  diges- 
tion and  reabsorbed.  Part  is 
a  true  excretion  (bile  pig- 
ments). 

Milk 

Mammary  glands 

Alkaline 

Food. 

Sebum 

Sebaceous  glands 
of  the  skin 

AlkaUne 

To  oil  the  skin. 

Sweat 

Sweat-glands   of 

Acid 

Elimination  of  water,   carbon 

skin 

dioxide,  and  urea.  Helps  to 
regulate  body-temperature. 

Vaginal 

Vagina 

Acid 

Lubricant,  moistening  and  pro- 
tection. 

Urine 

Kidneys                  Acid 

Elimination  of  water  and  urea. 

Vascular  System  • 


CHAPTER  IX 

VASCULAR   SYSTEM;     THE   BLOOD    AND    LYMPH 

It  is  helpful  to  remember  that  the  body  consists  of  an  enormous 
number  of  individual  cells,  and  that  each  cell  must  be  supplied 
with  materials,  to  enable  it  to  carry  on  its  activities,  and  at  the 
same  time  it  must  have  the  waste  materials  that  are  the  result  of 
its  activities  removed.  Many  cells  are  far  from  the  source 
of  supplies  and  the  organs  of  elimination ;  hence  the  need  of  a 
medium  to  distribute  supplies  and  collect  waste,  and  the  need  of  a 
system  so  that  the  distribution  will  be  orderly  and  systematic. 
These  two  needs  are  met  by  the  vascular  system,  the  divisions  of 
which  may  be  outlined  as  follows  :  — 

Circulating  fluids  I  ^         , 

„     ,  I  Blood  vascular 

Systems  1  t         i  i 

•^  I  Lymph  vascular. 

THE  BLOOD 

Characteristics.  — ■  The  most  striking  external  feature  of  the 
blood  is  its  well-known  color,  which  is  bright  red,  approaching  to 
scarlet  in  the  arteries,  but  of  a  dark  red  or  crimson  tint  in  the  veins. 

It  is  a  somewhat  sticky  liquid,  a  little  heavier  than  water; 
its  specific  gravity  is  about  L055.  It  has  a  peculiar  odor,  a  saltish 
taste,  a  slightly  alkaline  reaction  when  tested  with  litmus,  and  a 
temperature  of  about  100°  F.  (37.8°  C). 

Quantity  of  blood.  —  The  quantity  of  blood  contained  in  the 
body  is  estimated  to  be  about  2V  of  the  body  weight.  This  pro- 
portion was  formerly  said  to  be  about  -5^3,  but  later  experiments 
seem  to  place  the  figure  at  aV-  This,  in  an  individual  weighing 
160  pounds,  would  weigh  about  8  pounds,  or  measure  4  quarts. 

Functions  of  the  blood.  —  Blood  is  commonly  spoken  of  as 
the  nutritive  fluid  of  the  body.  This  is  quite  correct,  but  it  is 
more  than  a  nutritive  fluid,  as  will  be  seen  from  the  following 
list  of  its  more  important  functions  :  — 

141 


142 


ANATOMY  FOR  NURSES 


[Chap.  IX 


(1)  It  carries  to  the  tissues  water  and  the  nutritive  substances 
resulting  from  digestion.  These  are  required  by  each  individual 
cell  in  order  to  enable  it  to  carry  on  its  metabolic  processes. 

(2)  It  carries  to  the  tissues  oxygen,  absorbed  from  the  air 
in  the  lungs.  Every  individual  cell  requires  oxygen,  in  order  to 
provide  heat  and  energy. 

(3)  It  carries  from  the  tissues  various  waste  ])roducts.  These 
are  not  only  useless,  but  poisonous,  and  must  be  eliminated  by  the 
lungs,  kidneys,  and  skin. 

(4)  It  serves  as  a  medium  for  the  transmission  of  certain 
secretions.  The  presence  of  these  secretions  promotes  oxidation 
and  metabolism. 

(5)  It  aids  in  equalizing  the  temi)erature  of  the  body.  Blood 
passing  through  a  tissue  which  is  undergoing  lively  metabolism 
will  have  a  higher  temperature  when  it  leaves  than  it  had  when  it 
entered.  This  extra  temperature  will  be  lost  in  passing  through 
a  tissue  that  is  not  so  active.  In  this  way  an  average  temperature 
is  maintained. 

(())  It  aids  in  protecting  the  body  from  infections. 

Composition  of  the  blood.  —  Seen  with  the  naked  eye,  the 
blood  appears  opaque  and  homogeneous ;  but  when  examined 
with  a  microscope  it  is  seen  to  consist  of  minute,  solid  particles 
called  corpuscles,  floating  in  a  transparent,  slightly  yellowish  fluid 
called  plasma. 

Red  or  erj'throcytes. 
Corpuscles  \  White  or  leucocjrtes. 
Blood  plates. 
Water,  £0  %. 
Blood  {  Proteins. 

Extractives. 
Inorganic  salts. 
Gases. 
Enzj'^mes. 
Internal  secretions. 
Immune  bodies. 

Red  corpuscles.  —  The  red  corpuscles  are  circular  biconcave 
disks,  with  rounded  edges.  The  average  size  is  s^^-q  of  an  inch 
(0.008  mm.)  in  diameter,  and  about  12^0^  (0.002  mm.)  of  an  inch 
in  thickness.  Because  of  their  extremely  small  size,  the  red  cor- 
puscles do  not  appear  red  when  viewed  singly  with  a  microscope, 


Plasma 


Chap.  IX]  VASCULAR  SYSTEM  143 

but  merely  of  a  reddish  yellow  tinge,  or  yellowish  green  in  venous 
blood.  It  is  only  when  great  numbers  of  them  are  gathered 
together  that  a  distinct  red  color  is  produced. 

Authorities  differ  regarding  the  structure  of  the  red  corpuscles. 
Some  describe  them  as  consisting  of  a  colorless  filmy,  elastic  frame- 
work infiltrated  in  all  parts  by  a  red  coloring  matter  termed 
haemoglobin,  which  contains  a  small  amount  of  iron.  Others 
describe  them  as  consisting  of  a  colorless  elastic  envelope  enclosing 
a  solution  of  haemoglobin.  In  either  case  it  is  correct  to  consider 
them  as  packets  of  haemoglobin  moving  passively  at  the  mercy  of 
the  blood  current.  They  have  no  nuclei,  are  soft,  flexible,  and 
elastic,  so  that  they  readily  Squeeze  through  apertures  and  passages 
narrower  than  their  own  diameters,  and  immediately  resume  their 
proper  shape. 

Function  of  the  red  corpuscles.  —  The  red  corpuscles,  or  eryth- 
rocytes, by  virtue  of  the  haemoglobin  which  they  contain,  are 
emphatically  oxygen  carriers.  Exposed  to  the  air  in  the  lungs  the 
heemoglobin  becomes  fully  charged  with  detachable  oxygen  and 
is  known  as  oxyhsemoglobin.  The  red  corpuscles  carry  this 
oxyhsemoglobin  to  the  tissues,  where  it  gives  up  the  loosely  en- 
gaged oxygen.  It  is  then  known  as  reduced  haemoglobin  and  is 
ready  to  be  carried  to  the  lungs  for  a  fresh  supply.  The  color  of 
the  blood  is  dependent  upon  this  combination  of  the  haemoglobin 
with  oxygen ;  when  the  haemoglobin  has  its  full  complement  of 
ox^'gen,  the  blood  has  a  bright  red  hue ;  when  the  amount  is  de- 
creased, it  changes  to  a  dark  crimson  hue.  The  scarlet  blood  is 
usually  found  in  the  arteries,  and  is  called  arterial;  the  dark 
crimson  in  the  veins,  and  is  called  venous  blood. 

Life  cycle  of  the  red  corpuscles.  —  There  is  every  reason  to 
believe  that  the  red  corpuscles,  like  all  the  cells  of  the  body,  have  a 
definite  term  of  existence,  then  disintegrate  and  are  replaced  by 
other  corpuscles.  They  originate  in  the  red  marrow  of  the  bones, 
but  in  case  of  special  need,  as  after  the  loss  of  a  large  number  by 
hemorrhage,  they  can  be  formed  in  other  organs,  especially  the 
spleen.  Before  being  forced  into  the  blood  stream  they  lose  their 
nuclei,  and  this  suggests  that  they  do  not  live  a  great  while  in  the 
circulation.  Red  corpuscles  in  various  stages  of  disintegration 
have  been  found  in  the  substance  of  the  spleen  and  lymph  nodes. 
Some  authorities  consider  that  their  destruction  takes  place  in 


144  ANATOMY  FOR  NURSES  [Chap.  IX 

these  organs,  but  others  consider  that  it  takes  place  in  the  blood 
in  any  part  of  the  system. 

Number  of  red  corpuscles.  —  The  average  number  of  red  cor- 
j)uscles  in  a  cubic  niillinietre  of  healthy  blood  is  given  as  5,000,000 
for  men  and  4,500,000  for  women.  Even  in  health  this  number 
varies  and  in  disease  it  may  be  greatly  reduced.  An  increase  in 
temperature  hastens  the  destruction  of  red  corpuscles,  and  in  this 
way  causes  a  reduction  in  number.  The  condition  known  as 
anemia  may  be  due  to  a  diminished  number  of  red  corpuscles,  which 
means  a  diminished  supply  of  ox^'gen,  and  a  consequent  inter- 
ference with  the  processes  of  metabolism. 

White  corpuscles.  —  The  white  corpuscles  are  masses  of  proto- 
plasm containing  a  nucleus,  sometimes  even  two  or  three  nuclei, 
and  they  have  no  cell  wall.  Their  form  is  very  various,  but  when 
they  are  carried  along  in  the  blood  current,  or  when  the  blood  is 
first  drawn,  they  are  rounded  or  spheroidal.  Measured  in  this 
condition,  they  are  about  osVcr  of  an  inch  (0.010  mm.)  in  diameter. 
The  white  corpuscle  may  be  taken  as  the  type  of  a  free  animal 
cell. 

Number  of  white  corpuscles.  —  The  average  number  of  white 
corpuscles  in  a  cubic  millimetre  of  healthy  blootl  is  from  7000  to 
9000,  or  in  the  proportion  of  1  white  to  500  or  600  red.  A  marked 
increase  in  number  is  designated  as  leucocytosis,  a  marked  decrease 
as  leiicopenia.  Under  various  normal  conditions,  such  as  digestion, 
exercise,  or  cold  baths,  leucocytosis  occurs.  It  also  occurs  under 
abnormal  conditions,  and  a  knowledge  of  the  variations  under 
pathological  conditions  is  an  important  aid  in  diagnosis. 

Varieties  of  white  corpuscles.  —  At  least  five  varieties  have 
been  studied  and  described.  They  are  classified  under  two  main 
groups :  — 

(1)  Leucocytes. 

(2)  Lymphocytes. 

The  most  marked  difference  is  in  the  nuclei  and  in  the  amount 
of  amoeboid  movement  exliibited.  The  difference  is  said  to  be 
due  solely  to  the  age  of  the  corpuscle  —  the  lymphoc\'te  being  the 
more  recently  formed,  and  in  time  will  change  into  a  leucocyte. 
Each  of  these  groups  may  be  subdivided  into  two  or  more 
subgroups,  and  some  authorities  hold  that  each  variety  has  some 
special  function,  but  this  has  not  been  proven. 


Chap.  IX]  VASCULAR  SYSTEM  145 

Amoeboid  movements.  —  One  distinctive  property  of  white 
blood  corpuscles  is  their  power  of  making  amoeboid  movements, 
which  enables  them  to  change  their  form  and  escape  through  the 
walls  of  the  blood  capillaries  into  the  surrounding  tissues.  This 
property  has  earned  for  them  the  title  of  wandering  cells,  and  the 
process  is  spoken  of  as  migration.  It  occurs  under  normal  condi- 
tions, but  is  vastly  accelerated  under  pathological  conditions. 

Function  of  the  white  corpuscles.  —  It  is  definitely  known  that 
they  act  (1)  as  protective  agents,  (2)  aid  in  the  absorption  of  fats 
and  proteins  from  the  intestines,  and  (3)  assist  in  the  coagulation 
of  the  blood. 

Their  function  of  protection  is  very  important,  and  is  accom- 
plished in  two  ways  :  — 

(a)  By  forming  certain  substances  called  bacteriolysins,  which 
when  imbibed  by  bacteria  kills  them  ;  (b)  by  virtue  of  their  amoe- 
boid movements  they  can  creep  around  bacteria,  envelop  them 
with  their  own  substance,  and  so  put  them  inside  themselves. 
This  process  is  called  phagocytosis,  and  has  earned  for  them  the 
name  of  phagocytes. 

Opsonins.  —  This  is  a  name  given  to  chemical  substances  found 
in  blood  plasma.  The  function  of  an  opsonin  ^  is  to  prepare  certain 
disease  germs  for  destruction  and  absorption  by  the  white  cor- 
puscles of  the  blood.  The  phagocytic  properties  of  the  leucocytes 
become  especially  developed  as  the  result  of  the  action  of  opsonins. 

Inflammation.  —  When  any  of  the  tissues  become  inflamed 
either  as  the  result  of  injury  or  infection,  the  first  effect  is  irritation, 
followed  by  an  increased  supply  of  blood  to  the  part.  If  the  irri- 
tation continues  or  is  severe,  the  flow  of  blood  begins  to  slacken, 
and  a  condition  of  stasis  or  engorgement  results.  The  white 
corpuscles  become  particularly  active  and  migrate  into  the  infected 
tissues  in  large  numbers.  Some  of  the  blood  plasma  exudes,  and  a 
small  number  of  red  corpuscles  are  forced  through  the  capillary 
walls.2  This  general  condition  is  described  as  inflammation,  and 
the  symptoms  of  pain,  heat,  redness,  and  swelling  are  due,  (1)  to 
the  increased  supply  of  blood,  (2)  to  the  engorgement  of  the  blood- 
vessels, and  (3)  to  the  collection  of  fluid  in  the  tissues,  which  is 

1  From  opso'no,  I  prepare  food  for. 

"  This  passive  ability  of  red  corpuscles  to  pass  through  the  capillary  walls  is 
called  diapedesis. 


146  ANATOMY   FOR   NURSES  [Chap.  IX 

spoken  of  as  inflammatory  exudate.  Under  these  conditions  a 
death  struggle  between  the  leucocytes  and  bacteria  takes  place. 
If  the  leucocytes  are  victorious,  they  not  only  kill  the  bacteria  but 
remove  every  vestige  of  the  struggle,  and  find  their  way  back  to 
the  blood.  If  the  bacteria  are  victorious,  and  suppuration  ensues, 
the  leucocytes  become  pus  corpuscles.  Also,  in  the  case  of  a 
wound,  the  leucocytes,  by  virtue  of  their  amoeboid  movements, 
escape  from  the  blood-vessels,  accumulate  in  the  region  of  the 
wound,  and  act  as  barriers  against  infection. 

Life  cycle  of  the  white  corpuscles.  —  It  is  presumed  that  the 
white  corpuscles  like  all  other  cells  have  a  definite  term  of  existence. 
We  do  not  know  the  length  of  this  term,  or  where  they  are  de- 
stroyed, except  that  large  numbers  are  lost  in  the  battle  waged 
against  bacteria,  others  by  hemorrhage,  and  others  may  be  con- 
verted into  granulation  tissue.  These  lost  leucocytes  are  replaced 
by  new  leucocytes  which  result  from  the  division  of  former  leuco- 
cytes. This  division  usually  takes  place  in  the  lymph  nodes  and 
the  spleen. 

Differences  between  white  and  red  corpuscles.  — 

(1)  White  blood-cells  are  larger  than  red  corpuscles,  but  normally 
are  present  in  smaller  numbers. 

(2)  They  have  no  pigment  or  haemoglobin,  hence  are  colorless. 

(3)  On  account  of  the  property  of  amoeboid  movement  their 
shape  varies. 

(4)  They  always  have  a  nucleus,  sometimes  two  or  three  nuclei. 

(5)  There  are  five  varieties  that  differ  in  microscopical  structure 
and  possibly  in  function. 

(6)  During  circulation  they  keep  close  to  and  even  seem  to 
adhere  to  the  walls  of  the  vessels,  while  the  red  corpuscles  keep 
in  the  middle  of  the  stream. 

(7)  By  virtue  of  their  amoeboid  movement  they  escape  through 
the  walls  of  the  capillaries  and  are  found  in  the  tissue  spaces. 
They  are  also  found  in  lymph,  chyle,  and  pus. 

(8)  The  functions  of  the  white  blood-cells  are  quite  different 
from  the  red  corpuscles. 

Blood-plates.  —  They  are  small,  pale  yellow,  or  colorless  disks 
of  which  little  is  known.  They  vary  in  size  and  shape,  but  are 
always  smaller  than  the  red  corpuscles.  It  is  not  decided  whether 
they  are  to  be  considered  as  independent  cells  or  as  fragments 


Chap.  IX] 


VASCULAR  SYSTEM 


147 


of  disintegrated  cells.  The  number  is  usually  about  yV  the  number 
of  red  corpuscles. 

Function.  —  When  the  blood  leaves  the  blood-vessels  and  comes 
in  contact  with  foreign  matter,  the  blood-plates  and  some  of  the 
white  corpuscles  disintegrate  and  give  rise  to  a  substance  called 
prothrombin.  This  is  acted  upon  by  substances  in  the  blood 
plasma  and  converted  into  thrombin,  which  is  one  of  the  essentials 
for  the  formation  of  a  clot. 

Plasma.  —  The  plasma  of  the  blood  is  of  a  clear,  slightly  yel- 
lowish color.  It  consists  for  the  most  part  of  water  charged  with 
nutritive  matter  derived  from  our  food,  and  waste  matter  derived 
from  the  tissues.  In  other  words,  it  consists  of  water  holding  in 
solution  or  suspension  :  — 

r  Serum-albumin. 
Proteins .     .     .     .  <  Para-globulin  or  serum-globulin. 
I  Fibrinogen. 

Sugars. 

Fats. 

Lecithin 

Cholesterin 

Urea 

Uric  acid 

Hippuric  acid 

Creatin 


Extractives 


Represent  waste  products. 


Inorganic  Salts 


Gases      .     . 

Enzymes 

Internal  Secretions 

Immune  Bodies 


Chlorides 
Sulphates 
Phosphates 
Carbonates 

( Ox.vgen. 

<  Nitrogen. 

I  Carbon  Dioxide. 


of 


Sodium. 

Calcium. 

Magnesium. 


( Opsonins. 

I  Antitoxins. 

I  Antibacterial  substances. 


Proteins.  —  There  are  many  indications  which  support  the 
belief  that  the  actual  number  of  individual  proteins  is  much  greater 
than  the  usual  three  mentioned  in  our  list.  Our  knowledge  of 
these  substances,  and  of  the  particular  value  of  each  one  in  the 
system  is  limited. 


148  ANATOMY  FOR   NURSES  [Chap.  IX 

Serum-albumin  belongs  to  the  group  of  albumins  of  which  white 
of  egg  is  a  member  and  holds  the  first  place  in  regard  to  nutrition. 
It  represents  the  protein  portion  of  our  food  supply  and  the 
greater  part  of  the  material  necessary  for  the  daily  nourishment 
and  renovation  of  the  tissues.  In  this  process  it  undergoes  a 
variety  of  transformations,  by  which  it  is  converted  into  the  struc- 
tural characteristics  of  the  tissues  which  it  supplies. 

Para-globulin  ^  belongs  to  the  class  of  globulins.  The  origin 
and  function  are  undecided.  It  may  be  a  source  of  nitrogenous 
food,  and  assists  in  coagulation  of  the  blood. 

The  serum-albumin  and  para-globulin  occur  in  about  equal  quan- 
tities. 

Fibrinogen  belongs  to  the  class  of  globulins,  and  is  the  sub- 
stance which  produces  the  fibrin  of  coagulated  blood.  It  is  very 
difficult  to  obtain  in  the  fluid  condition,  owing  to  the  rapidity  with 
which  it  solidifies  when  blood  is  withdrawn  from  the  circulation. 
Though  it  is  a  most  important  element  in  the  blood,  it  occurs  in 
very  small  quantities. 

Extractives.  —  Extractives  are  substances  other  than  proteins 
that  may  be  extracted  from  dried  blood  by  special  methods. 

Sugar  in  the  form  of  glucose  is  present  under  normal  condi- 
tions in  the  amount  of  0.1  to  0.2  per  cent.  A  temporary  in- 
crease in  the  amount  of  sugar  may  follow  the  ingestion  of  a  large 
quantity. 

Fat  is  found  in  the  plasma  in  about  the  same  proportion  as 
sugar.  It  is  much  more  subject  to  variation,  rising  notably 
after  a  meal  in  which  there  was  much  fat. 

Waste  products  found  in  the  plasma  represent  the  end  products 
resulting  from  the  oxidation  of  our  food.  Due  to  the  efficiency  of 
the  kidneys  and  supplementary  organs  of  excretion  they  occur 
in  very  small  quantities. 

Salts. — The  salts  found  in  the  blood  amount  to  about  one  per  cent 
of  the  total  solids.  They  are  derived  from  the  food  and  from  the 
chemical  reactions  going  on  in  the  body.  The  most  abundant  is 
sodium  chloride. 

Gases.  —  OxA'gen,  nitrogen,  and  carbon  dioxide  gas  are  found 
in  the  blood.     Carbon  dioxide  is  the  result  of  oxidation  in  the 

'  Albumins  and  globulins  give  the  same  general  tests ;  they  are  both  coagulated 
by  heat,  and  the  chief  difference  is  in  their  solubilities. 


Chap.  IX] 


VASCULAR  SYSTEM 


149 


tissues,  and  is  found  in  both  arterial  and  venous  blood,  but  the 
quantity  is  greater  in  venous  blood. 

Enzymes. — An  enzyme  is  a  substance  produced  by  living  cells 
and  is  capable  of  effecting  chemical  change  without  itself  undergo- 
ing alteration  in  the  process.  Each  enzyme  has  a  definite  action  at 
a  suitable  temperature,  and  will  only  work  in  a  medium  of  definite 
reaction,  either  acid  or  alkaline.  Further  the  products  of  the 
action  must  be  removed.  Five  enzymes  have  been  found  in  the 
blood. 

Internal  secretions.  —  The  blood  serves  as  a  medium  to  carry 
internal  secretions.     (See  page  136.) 

Immune  bodies.  —  In  addition  to  the  phagocytes  and  opsonins, 
the  blood  has  been  found  to  contain  various  other  protective  sub- 
stances, which  are  described  as  antibodies.  Just  how  they  are 
formed,  and  whether  they  are  a  natural  constituent  of  the  blood, 
or  whether  they  are  developed  only  during  an  attack  of  disease, 
are  undecided  questions.  The  antibodies,  like  the  enzymes,  are 
specific  in  their  action,  that  is,  each  variety  will  act  against  only 
one  form  of  bacterium  or  toxin ;  for  instance  the  antibody  for 
typhoid  is  of  no  service  against  pneumonia. 

THE  CLOTTING   OF  BLOOD 

Blood  when  drawn  from  the  blood-vessels  of  a  living  body  is 
perfectly  fluid.  In  a  short  time  it  becomes  viscid,  and  this  vis- 
cidity increases  rapidly  until  the  whole  mass  of  blood  becomes  a 


Fig.  95.  —  Bowl  of  Recently 
Clotted  Blood,  showing  the  Whole 
Mass  uniformly  Solidified.  (Dal- 
ton.) 


Fig.  96.  —  Bowl  of  Clotted  Blood 
AFTER  Twelve  Hours,  showing  the 
Clot  Contracted  and  Floating  in 
the  Fluid  Serum.     (Dalton.) 


complete  jelly.  If  the  blood  in  this  jelly  stage  be  left  untouched 
in  a  glass  vessel,  a  few  drops  of  an  almost  colorless  fluid  soon  make 
their  appearance  on  the  surface  of  the  jelly.-    Increasing  in  number 


150  ANATOMY   FOR   NURSES  [Chap.  IX 

and  running  together,  the  drops  after  a  while  form  a  superficial 
layer  of  pale  straw-colored  fluid.  Later  on,  similar  layers  of  the 
same  fluid  are  seen  at  the  sides,  and  finally  at  the  bottom  of  the 
jelly,  which,  shrunk  to  a  smaller  size  and  of  firmer  consistency, 
now  forms  a  clot,  floating  in  a  liquid.  The  upper  surface  of 
the  clot  is  generally  slightly  concave.  If  a  portion  of  the  clot 
be  examined  under  the  microscope,  it  is  seen  to  consist  of  a  net- 
work of  fine  fibrils,  in  the  meshes  of  which  are  entangled  the  red 
and  some  of  the  white  corpuscles  of  the  blood.  The  fibrils  are 
composed  of  the  fibrin ;  and  the  liquid  in  which  the  clot  is  sus- 
pended is  blood  minus  corpuscles  and  fibrin,  and  is  called  serum. 
The  relation  between  plasma  and  serum  is  shown  in  the  following 

scheme :  — 

Serum 


^,     ^     Plasma 
Blood  I 


Corpuscles 


Fibrin 


Clot 


.  The  formation  of  insoluble  fibrin  from  soluble  fibrinogen  is  an 
instance  of  enzyme  action  and  is  comparable  to  the  clotting  of 
milk  under  the  influence  of  rennin.  When  blood  leaves  the  vessels, 
the  blood-plates  and  some  of  the  white  corpuscles  luidergo  prompt 
disintegration,  and  give  rise  to  a  substance  called  prothrombin, 
which  is  acted  upon  by  the  calcium  salts  of  the  plasma  and  con- 
verted into  thrombin.  It  is  this  substance  called  thrombin  which 
acts  upon  the  fibrinogen  and  converts  it  into  fibrin. 

Value  of  clotting.  —  This  property  is  of  very  great  im- 
portance in  the  arrest  of  hemorrhage.  The  clot  formed  closes 
the  openings  of  wounded  vessels,  and  the  procedures  used  to  check 
hemorrhage  are  directed  toward  hastening  the  formation  of  a  clot, 
and  stimulating  the  blood-vessels  to  contract  so  that  a  smaller- 
sized  clot  will  be  sufficient. 

The  coagulability  of  the  blood  differs  in  different  individuals, 
and  in  rare  cases  is  so  slight  that  the  most  trivial  operation  involv- 
ing hemorrhage  is  attended  with  great  danger.  This  condition 
is  known  as  hemorrhagic  diathesis  or  hemophilia,  and  is  thought 
to  be  due  to  a  lack  of  fil)rinogen  or  of  calcium  salts. 

Conditions  affecting  clotting.  —  Clotting  is  hastened  by :  — 

(1)  A  temperature  higher  than  that  of  the  body,  110-120°  F. 

(2)  Contact  with  any  rough  surface. 

(3)  Contact  with  any  foreign  substance,  such  as  gauze.  • 


Chap.  IX]  VASCULAR  SYSTEM  151 

(4)  Injury  to  the  walls  of  the  blood-vessels. 

(5)  Rest. 

It  is  generally  conceded  that  the  first  four  conditions  hasten  the 
disintegration  of  blood-plates  and  white  corpuscles,  and  conse- 
quently the  formation  of  thrombin  and  of  a  clot.  Many  standard 
text-books  include  agitation  instead  of  rest.  If  blood  is  contained 
in  a  vessel,  agitation  of  it  does  hasten  the  process  of  clotting  in 
the  same  way  that  the  first  four  conditions  do.  If,  however,  we 
consider  the  formation  of  a  clot  in  the  open  end  of  an  injured 
vessel,  we  keep  the  part  at  rest,  because  agitation  might  dislodge 
the  clot  after  it  had  formed. 

Clotting  is  hindered  by :  — 

(1)  A  very  low  temperature.  Cold  hinders  the  formation  of  a 
clot  but  is  often  used  to  check  hemorrhage,  because  it  stimulates 
the  blood-vessels  to  contract. 

(2)  Contact  with  living  tissues,  especially  the  walls  of  the  blood- 
vessels. 

(3)  The  addition  of  strong  acids  or  alkalies,  neutral  salts,  oil 
or  other  viscid  substances,  certain  organic  ferments,  or  a  large 
quantity  of  water. 

(4)  Absence  of  calcium  salts. 

(5)  Absence  of  fibrinogen. 

(6)  Removal  of  fibrin.  If  fresh  blood,  before  it  has  time  to 
clot,  be  whipped  with  a  bundle  of  twigs,  the  fibrin  will  form  on 
the  twigs,  and  if  the  whipping  of  the  blood  be  continued  until 
after  the  fibrin  has  been  deposited  on  the  twigs,  the  blood  left  in 
the  vessel  will  be  found  to  have  lost  the  power  of  clotting.  Such 
blood  is  called  defibrinated. 

Why  blood  does  not  clot  within  the  blood-vessels.  —  Fortunately 
blood  rarely  clots  within  the  blood-vessels  during  life.  Why  it 
does  not  is  not  known,  but  two  theories  are  advanced  to  account 
for  it. 

(1)  Circulating  blood  does  not  contain  thrombin  because  the 
blood-plates  and  white  corpuscles  do  not  disintegrate  in  sufficient 
numbers  to  allow  for  the  formation  of  it. 

(2)  Circulating  blood  does  contain  some  thrombin,  but  it 
also  contains  a  substance  called  antithrombin  which  is  secreted 
by  the  lining  of  the  heart  and  blood-vessels.  Antithrombin 
neutralizes  or  prevents  the  activity  of  thrombin. 


152  ANATOMY   FOR   NURSES  [Chap.  IX 

Intravascular  clotting.  —  It  is  well  known  that  clots  occasionally 
form  within  tlie  blood-vessels.     The  most  frequent  causes  are :  — 

(1)  When  the  internal  coat  of  a  blood-vessel  is  injured,  as  for 
instance  by  a  ligature,  the  endothelial  cells  are  altered  and  may 
act  as  a  foreign  substance.  If  in  addition  there  is  a  stasis  of 
blood  at  this  point,  disintegration  of  the  blood-plates  and  white 
corpuscles  may  result  in  the  formation  of  thrombin  and  a  clot. 

(2)  Any  foreign  material,  even  air,  that  is  introduced  into  the 
blood  and  not  absorbed  may  stimulate  the  formation  of  thrombin 
and  a  clot. 

Thrombus  and  embolus.  —  A  clot  which  forms  inside  a  blood- 
vessel is  called  a  thrombus.  A  thrombus  may  be  broken  up  and 
disappear,  but  the  danger  is  that  it  may  be  carried  to  some  point 
in  an  important  vessel  where  it  acts  as  a  wedge,  blocks  circulation, 
and  may  cause  instant  death.  A  thrombus  that  becomes  dislodged 
from  its  place  of  formation  is  called  an  embolus. 

Regeneration  of  the  blood  after  hemorrhage.  —  A  large  portion 
of  the  total  amount  of  blood  in  the  body  may  be  lost  suddenly  by 
hemorrhage  without  producing  a  fatal  result.  It  is  probable 
that  a  healthy  individual  may  recover  from  the  loss  of  as  much  as 
three  per  cent  of  the  body  weight,  provided  the  lost  blood  is  at  once 
replaced  by  a  solution  having  the  same  degree  of  concentration, 
and  containing  one  or  more  of  the  important  salts  of  the  blood. 
Physiological  saline  solution,  ?'.<?.,  sodium  chloride  0.7  to  0.9  per  cent, 
fulfills  these  conditions,  and  is  usually  introduced  directly  into  a 
vein.  This  operation  is  called  intravenous  infusion,  and  the  bene- 
fits derived  from  it  are  :  — 

(1)  The  heart-beat  is  increased,  because  it  must  make  stronger 
contractions  to  propel  the  extra  fluid. 

(2)  The  volume  of  the  circulating  fluid  is  sufficiently  increased 
to  maintain  normal  conditions  of  pressure  and  velocity. 

(3)  The  red  corpuscles  are  kept  in  rapid  circulation  and  thus 
loss  of  oxygen  to  the  tissues  is  prevented. 

(4)  The  tissue  cells  are  provided  with  water  and  thus  protected 
from  the  bad  effects  that  would  follow  the  withdrawal  of  water. 

Plasma  is  regenerated  with  some  rapidity  but  it  may  take 
days  or  even  weeks  before  the  number  of  red  blood  corpuscles 
and  the  haemoglobin  gets  back  to  normal. 


Chap.  IX] 


VASCULAR  SYSTEM 


153 


LYMPH 

Lymph  is  a  pale,  straw-colored  liquid  that  bathes  all  the  tissue- 
spaces  of  the  body.  It  is  slightly  alkaline,  has  a  salty  taste,  and 
no  odor.  When  examined  with  the  microscope,  it  is  seen  to  con- 
sist of  a  clear  liquid  with  white  corpuscles  floating  in  it.  In  com- 
position it  resembles  the  blood,  the  essential  differences  being :  — 


Blood 

Lymph 

Specific  gravity  about  L055 

Specific  gravity  about  1.015 

Contains  red  corpuscles 

Does  not  contain  red  corpuscles 

Contains  white  corpuscles 

Does  contain  white  corpuscles 

Contains  blood-plates 

Does  not  contain  blood-plates 

A  high  content  of  proteins 

A  low  content  of  proteins 

A  low  content  of  waste  products 

A  higher   content   of   waste   prod- 

ucts, particularly  carbon  dioxide 

and  urea 

Normally  —  clots  quickly  and  firmly 

Clots   slowly  and    does    not   form 

a  firm  clot 

Sources  of  lymph.  —  During  the  passage  of  the  blood  through 
the  thin-walled  capillaries,  the  plasma  is  forced  to  transude  into 
such  spaces  as  exist  between  the  cells  of  the  tissues.  In  addition 
to  this  transudation  it  is  necessary  to  assume  an  active  secretory 
process  on  the  part  of  the  endothelial  cells  composing  the  capillary 
walls.  This  plasma  plus  the  leucocytes  that  have  left  the  vessels 
by  migration  make  up  the  lymph  proper.  Besides  the  lymph 
proper,  the  lymph  that  fills  the  lacteals  of  the  intestinal  villi  ab- 
sorbs some  of  the  products  of  digestion,  especially  the  fats. 

This  portion  of  the  lymph  that  has  absorbed  the  fats  is  milky  in 
appearance,  and  is  called  chyle.  The  lymph,  broadly  speak- 
ing, is  dilute  blood  minus  its  red  corpuscles.  The  chyle  is  lymph 
plus  a  very  large  quantity  of  minutely  divided  fat. 

Functions  of  the  lymph.  —  The  lymph  bathes  all  portions  of  the 
body  not  reached  by  the  blood.  Hence  the  lymph  conveys  the 
nutrient  ingredients  of  the  blood  to  all  cells  not  directly  bathed  by 
the  blood.  It  delivers  to  the  cells  the  material  each  cell  needs  to 
maintain  its  functional  activity,  and  picks  up  and  returns  to  the 
blood  the  products  of  this  activity,  which  products  may  be  simple 
waste,  or  matters  capable  of  being  made  use  of  by  some  other 


154  ANATOMY  FOR  NURSES  [Chap.  IX 

tissue.  There  is  thus  a  continual  interchange  going  on  between 
the  blood  and  the  lymph.  This  interchange  is  effected  in  two 
ways :  — 

{\)  By  dialysis.  — The  lymph  becomes  altered  by  the  metabolic 
changes  of  the  tissues  which  it  bathes,  and  we  have  two  different 
fluids,  separated  by  the  moist  membrane  which  forms  the  walls 
of  the  blood-vessels,  —  the  lymph  in  the  tissues  outside  the  walls  of 
the  capillaries  and  the  blood  inside  the  capillary  walls.  Some  of 
the  constituents  of  the  lymph  pass  into  the  blood,  while  some 
of  the  constituents  of  the  blood  pass  into  the  lymph,  by  the  process 
of  dialysis.^ 

These  constituents,  which,  as  we  cannot  too  often  emphasize,  are 
products  resulting  from  the  activity  of  the  tissues,  are  carried  away 
by  the  blood  to  other  tissues,  which  will  either  make  use  of  them, 
or,  as  in  the  kidneys,  take  them  up  to  make  excretory  fluids, 
and  so  remove  them. 

(2)  By  osmosis.  —  The  blood,  on  account  of  the  higher  pressure, 
loses  more  liquid  to  the  lymph  than  it  receives  back  by  the  process 
of  osmosis.  This  excess  lymph  gathers  up  the  waste  materials 
of  the  cells  surrounding  the  lymph  spaces  and  through  the  medium 
of  the  lymphatics  pours  this  waste  into  the  blood,  to  be  eliminated 
by  the  skin,  lungs,  and  kidneys. 

In  consequence  of  the  different  wants  and  wastes  of  different 
tissues  at  different  times,  both  the  lymph  and  blood  must  vary  in 
composition  in  different  parts  of  the  body.  But  the  loss  and  gain 
is  so  fairly  balanced  that  the  average  composition  is  pretty  con- 
stantly maintained. 

The  chyle,  or  lymph  of  digestion,  absorbs  nutrient  materials 
(mostly  fat)  from  the  intestines  and  pours  this  food  into  the  blood 
current,  to  be  distributed  to  all  parts  of  the  body. 

1  See  page  12. 


Chap.  IX] 


SUMMARY 


155 


Vascixlar  System 


f  Circulating 
i       Fluids 

Systems 


SUMMARY 

f  Blood. 
I  Lymph. 

f  Blood  vascular. 
I  Lymph  vascular. 


Blood 


Color 


Bright  red  in  arteries. 
Dark  red  in  veins. 
Sticky  fluid. 

Specific  gravity,  about  1.055. 
Description    \  Alkaline    reaction    when    tested    with 
litmus. 
Temperature,  100°  F. 
Peculiar  odor.     Salty  taste. 
^V  of  the  body  weight. 

Carries  water  and  nutritive  substances 

to  the  tissues. 
Carries  oxygen  to  the  tissues. 
Carries  waste  products  from  the  tissues 

to  the  organs  of  elimination. 
Serves  as  a  medium  for  the  transmission 

of  secretions. 
Aids    in    protecting    the    body    from 

infections. 
,  Aids  in  equalizing  temperature. 

'  Corpuscles  (  Red  or  erythrocytes, 

(minute,  solid  I  White  or  leucocytes, 
particles)  I  Blood-plates. 


Functions 


Composition  \  ^, 

transparent, 
slightly  yel- 
lowish fluid 


Water,  90  %. 

Proteins. 

Extractives. 

Inorganic  salts. 

Gases. 

Enzymes. 

Immune  bodies. 


Red 
Corpuscles 


Biconcave     f  ^^^-g  in.  in  diameter, 
disks        I  xijW  in.  in  thickness. 
Description    \  Packets  of  haemoglobhn. 
Have  no  nuclei. 
.  Soft,  flexible,  and  elastic. 

C  Oxj'gen  carriers. 
Function        <  Color   due   to   oxygen   in  combination 
[      with  haemoglobin. 


15G 


ANATOMY  FOR   NURSES 


[Chap.  IX 


Life  Cycle    - 


Red 
Corpuscles 


Originate  in  red  marrow  of  bones. 
Lose  their  nuclei  before  being  forced  into  cir- 
culation. 

I'  Blood  stream. 
Disintegrate  probably  in  I  Spleen. 

I  Ljniiph  nodes. 


Cubic     milli- 


Number 


meter 
blood 


of 


5,000,000  for  men. 


4,500,000  for  women. 
I  Pathological  conditions  maj'  cause  decrease. 
Masses  of  protoplasm. 


Description ' 


Animal  cell 


Number 


White 
Corpuscles 


Varieties 


Functions 


Cubic     miUi- 
mcter      of ' 
blood 


Lymphocytes 


Leucocytes 


1.  Protective 
agents 


Nucleus   (sometimes     two    or 

three  nuclei). 
No  cell  wall. 
Round    or    spheroidal    when 

circulating  in  blood. 
ssVff  in.  in  diameter. 

f  7000  to  9000. 

1  white  to  500  or  600  red. 

]\Iarkcd     increase    =  leucocy- 

tosis. 
.  Marked  decrease  =  leucopenia. 

f  (a)  Small  and  mononuclear. 
I  (6)  Large  and  mononuclear. 

(a)  Transition  forms. 

(6)  Polynuclear  —  form  60  to 
75  ':'o  of  Ijulk  of  white 
corpuscles.  Eosinophiles  are 
a  subgroup  of  this  variety. 

(c)  Mast  cells  —  exist  in  small 
numbers. 

(a)  Form  Bacteriolysitis. 
(6)  Devour  bacteria  =  phagocy- 
tosis. 


Life  Cycle    • 


2.  Aid  in  absorption  of  fats  and  proteins. 

3.  Assist  in  coagulation  of  blood. 

New  leucocytes  formed  in  lymph   nodes   and 
spleen. 

(1)  Battles  against  bacteria. 

,,      ,        ...       (2)  Hemorrhage. 
Numbers  lost  m  {  '  .   „         ^-         c  i 

(3)  Formation   of    granula- 

lation  tissue. 


Chap.  IX] 


SUMMARY 


157 


Symptoms 


Inflammation  < 


Result 


Differences 
between 
white  and 
red 
corpuscles 


Blood-plates 


Irritation  resulting  from  injury  or  infection. 
Engorgement  of  blood-vessels. 
Migration  of  white  blood-cells. 
Diapedesis  of  red  blood-cells. 
Exudation  of  plasma. 

f  Pain. 
)  Heat. 
I  Redness. 
I  Swelling. 

(a)  Resolution  —  White  blood-cells  eat  up 
bacteria,  clear  up  debris,  and  return 
to  blood. 

(b)  Suppuration  —  Bacteria  destroy  white 
blood-cells  and  tissue  cells,  and  form 
pus. 

Plasma. 
Red  corpuscles. 
White  corpuscles. 
Tissue  cells. 

dead. 

living. 
Toxins     produced    by 
[  I     bacteria. 

1.  Size  and  number. 

2.  Color. 

3.  Property  of  amoeboid  movement  and  shape. 

4.  Nucleus  or  nuclei. 

5.  Varieties. 

6.  Location  during  circulation. 

7.  Migration.     Found  in  other  fluids. 

8.  Functions. 

Pale  yellow  or  colorless  disks. 

Size  and  shape  various ;  always  smaller  than 

red  corpuscles  and  about  ^V  the  number  of 

red. 
Stimulates  formation  of  thrombin. 


(c)    Pus  consists  of  . 


Bacteria 


Description 


I  Function 


158 


ANATOMY  FOR  NURSES 


[Chap.  IX 


Water,  90' 


Proteins 


Serum-albumin  represents  the  protein  portion  of 

our  food  supply. 
Para-globulin  assists  in  coagulation  of  blood. 
Fibrinogen    produces    the    fibrin    of    coagulated 

blood. 


Extractives   • 


Plasma  i 


Inorganic 
Salts 


Sugar 

Fats 

Lecithin 
Cholesterin 
Urea 
Uric  acid 
Hippuric  acid 
Creatin 


Chlorides 
Sulphates 
Phosphates 
Carbonates 


(  Normally  present  0.1  %  to  0.2  %. 
I  May  be  increased  after  ingestion 
i      of  large  amount. 

Derived  from  food. 

Amount  subject  to  wide  variations. 

Represent  waste  products,  result 
of  oxidation  of  food.  Nor- 
mallj-  present  in  small  quantities. 


r  Sodium 
of  <  Calcium 
I  Magnesiuni 


Derived  from 
our  food,  and 
also  result 
from  chemical 
reactions  in 
our  bodies. 

About  1  %  of 
solids. 


Gases 


Enzymes 


Five  in  blood  • 


■  Oxygen  obtained  from  air. 
Nitrogen  obtained  from  air. 
Carbon  dioxide   result   of   oxidation.     Found   in 

both  arterial  and  venous  blood. 
Organic  ferments  that  affect  chemical  changes, 
and  remain  unchanged  themselves. 
■  An  amylolj-tic. 
A  glycolytic. 
A  lipol)i;ic. 
A  proteolytic. 
,  A  coagulating. 
Internal 

Secretions  —  See  Chapter  VIII. 

Opsonins  —  Chemical    substances    that    prepare 
disease  germs  for  absorption  and  destruction 
by  phagocytes. 
Antitoxins  —  Chemical      substances     that     act 

against  toxins. 
Antibodies  —  Chemical      substances     that     act 
against  bacteria  or  protozoa. 


Immune 
Bodies 


Chap.  IX] 


SUMMARY 


159 


Clotting  . 


Description 


Serum 


Clot 


Process 


Intravascular 
Clotting 


Regeneration 
of  blood  after 
hemorrhage 


r  Water. 

I  Mineral  salts. 

I  Albumin. 

j  Fibrin  formed  from  fibrinogen. 

\  Corpuscles,  red  and  white. 
White  corpuscles  and  blood- 
plates  disintegrate,  and  give 
rise  to  prothrombin.  Pro- 
thrombin is  acted  upon  by 
calcium  salts  and  forms 
thrombin.  Thrombin  acts  as 
ferment  or  enzyme. 

Value Checks  hemorrhage. 

Hemophilia  .  .  Lack  of  coagulabihty  of  the  blood. 

'  A  temperature  higher  than  that  of  body, 

110-120°  F. 
Contact  with  any  rough  surface. 
Contact  with  foreign  substances. 
Injury  to  the  walls  of  the  vessels. 
Rest. 


Hastened  by  < 


Hindered  by  < 


'  A  very  low  temperature. 
Contact    with    Uving    tissues,    especially 

blood-vessels. 
Addition  of  acids,  alkaUes,  neutral   salts, 

oils,  ferments,  water. 
Absence  of  calcium  salts. 
Absence  of  fibrinogen. 
Removal  of  fibrin.     (Defibrinated  blood.) 

^1.  Circulating    blood    does    not    contain 

thrombin. 
2.  Circulating  blood  does  contain  throm- 
bin,   but   it    is    counteracted   by  anti- 
thrombin. 

r  Injury  to  internal  coat  of  blood-vessels. 
I  Any  foreign  material  that  will  stimulate 
I      clotting. 

.  Name  given  to  clot  which  forms  inside 

vessel. 
.  A  thrombus  that    has   become   dislodged 

from  place  of  formation. 

If  immediate  ill  effects  are  counteracted  by  intravenous 
infusion,  plasma  is  regenerated  rapidly,  red  corpuscles 
in  comparatively  short  time. 


Theories  to 
account  for 
rare  occur- 
rence 


Causes 


Thrombus 


Embolus 


160 


ANATOMY  FOR  NURSES 


[Chap.  IX 


Intravenous 
Infusion 


Definition 


Benefits . 


Description. 


Lymph 


Sources. 


Function 


Injection  of  physiological  saline  solu- 
tion directly  into  vein. 

1.  Heart  stimulant. 

2.  Increases  volume  of  circulating  blood. 

3.  Red  corpuscles  kept  circulating,  and 
oxygen  supply  kept  up  as  far  as 
possible. 

4.  Cells  provided  with  water. 

Pale  straw-colored  liquid. 

Alkaline     reaction    when    tested    with 

litmus. 
Salty  taste.     No  odor. 
Consists    of    blood    plasma    plus    leu- 

cocji;es. 
Specific  gravity  about  1.015. 
Contains  a  low  content  of  proteins. 
Contains    a    high    content    of    waste 

products. 
Clots    slowh',    does    not    form    a    firm 

clot. 

Transudation  through  thin-walled  capil- 
laries. 

Active  secretory  process  on  part  of 
endothehal  cells. 

LjTTiph  acts  as  middleman  between  the 

blood  and  the  tissues. 
Carries    nourishment    from     blood    to 

tissues. 
Carries  waste  from  tissues  to  blood. 

1.  Dialysis. 

2.  Osmosis. 


Dependent  upon 


Chyle LjTnph  plus  nutrient  material,  mostly 

fats. 


CHAPTER  X 

THE   BLOOD   VASCULAR   SYSTEM,   AND    THE   LYMPH    VASCULAR 

SYSTEM 

BLOOD  VASCULAR  SYSTEM 

The  blood  is  the  internal  medium  on  which  the  tissues  live. 
It  is  carried  through  the  body  by  branched  tubes  named 
blood-vessels.  It  is  driven  along  these  tubes  by  the  action  of  the 
heart,  which  is  a  hollow  muscular  organ  placed  in  the  centre  of 
the  vascular  system.  One  set  of  vessels  —  the  arteries  —  conducts 
the  blood  out  from  the  heart  and  distributes  it  to  the  different 
parts  of  the  body,  whilst  other  vessels  —  the  veins  —  bring  it 
back  to  the  heart  again.  The  blood  from  the  arteries  gets  into  the 
veins  by  passing  through  a  network  of  fine  tubes  which  connect 
the  two,  and  which  are  named,  on  account  of  their  small  size,  the 
capillary  {i.e.  hair-like)  vessels. 


Blood  Vascular 
System 


f  Heart. 

Arteries  —  small  arteries  are  named  arterioles. 

Capillaries. 
.  Veins  —  small  veins  are  named  venules. 


We  shall  see  that  the  structure  of  these  several  parts  is  adapted 
to  their  respective  uses. 

HEART 

The  heart  is  a  hollow,  muscular  organ,  situated  in  the  thorax 
between  the  lungs,  behind  the  sternum,  and  above  the  central 
depression  of  the  diaphragm.  It  is  about  the  size  of  the  closed 
fist,  shaped  like  a  blunt  cone,  and  so  suspended  by  the  great 
vessels  that  the  broader  end  or  base  is  directed  upward,  back- 
ward, and  to  the  right.  The  pointed  end  or  apex  points  down- 
ward, forward,  and  to  the  left.  The  impulse  of  the  heart 
against  the  chest  wall  is  felt  in  the  space  between  the  fifth  and 
sixth  ribs,  a  little  below  and  to  the  inner  side  of  the  left  nipple. 
M  161 


162 


ANATOMY  FOR  NURSES 


[Chap.  X 


..-•*'?  ! 


Fig.  97.  —  He.^rt  in  situ  (Dalton,  in  Flint,  "On  the  Heart"),  a,  b,  c,  d,  e, 
ribs;  1,  2,  3,  4,  5,  intercostal  spaces;  vertical  line,  median  line;  triangle,  super- 
ficial cardiac  region  ;    X  on  the  fourth  rib,  nipple. 

As  placed  in  the  body,  it  has  a  very  oblique  position,  and  the  right 

side  is  almost  in  front  of 
the  left. 

Myocardium.  —  The 
main  substance  of  the 
heart  is  composed  of  mus- 
cular tissue  and  is  called 
myocardium.      (See  page 

m.) 

The  arrangement  of  ,the 
fibres  is  very  intricate ; 
they  run  transversely, 
longitudinally,  obliquely, 
and  in  the  apex  take  a 
spiral  turn  or  twist.  Be- 
tween the  muscle  fibres  is 
a  certain  amount  of  inter- 
stitial   tissue,    with    nu- 

FiG.  98.  —  Anterior  View  of  He.*.rt.  Dis-     meroUS  blood-vessels   and 

8ECTED,     AFTER    LONG    BoiLING,     TO    SHOW    THE  .  . 

Superficial  Muscular  Fibres.     (Quain.)  lymphatics,   and,  m  SOme 


Chap.  X] 


BLOOD   VASCULAR  SYSTEM 


163 


parts,  nerves  and  ganglia.  There  is  also  a  considerable  amount 
of  fat,  collected  chiefly  at  the  base  of  the  heart,  beneath  the 
pericardium. 

Pericardium.  —  The  heart  is  covered  by  a  membranous  sac 
called  the  pericardium  (around  the  heart.)     It  consists  of  two 


BRONCMlAL 
TUBES 


Fig.  99.  —  The  Pulmonary  Arterv  and  Aorta.  The  front  part  of  the  right 
lung  has  been  removed,  and  the  pulmonary  vessels  and  the  bronchial  tubes  are 
thus  exposed.     (Gerrish.) 

parts :   (1)  an  external  fibrous  portion,  and  (2)  an  internal,  serous 
portion. 

(1)  The  external  fibrous  pericardium  is  composed  of  white 
fibrous  tissue,  and  is  attached  by  its  upper  surface  to  the  large 
blood-vessels  which  emerge  from  the  heart.  It  covers  these  vessels 
for  about  an  inch  and  a  half  (38  mm.)  and  blends  with  their 
sheaths.  The  lower  border  is  firmly  adherent  to  the  diaphragm, 
and  the  front  surface  is  attached  to  the  sternum  by  means  of 
fibrous  bands. 


164 


ANATOMY   FOR  NURSES 


[Chap.  X 


ity ;    P.  P.    parietal   portion  of    pericardium ; 
V.P.  visceral  portion. 


(2)  The  internal  or  serous  portion  of  the  pericardium  is  a 
completely  closed  sac ;  it  envelops  the  heart  and  lines  the  fibrous 
pericardium.  The  heart,  however,  is  not  within  the  cavity  of 
the  closed  sac.     (See  Fig.    100.)     That    portion   of    the   serous 

pericardium  which  lines 
and  is  closely  adherent  to 
the  heart  is  called  the  vis- 
ceral portion  (visais  or- 
gan) ;  the  remaining  part 
of  the  serous  pericardium, 
namely,  that  which  lines 
the  fibrous  pericardium,  is 

Fig.  100.  —  Diagram  of  Heart  and  Se-  knowu  as  the  parietal  por- 
Rous  Pericardium.     In  .4,  heart  and  pcricar-     .•        /         •  U\        T*! 

dium  lying  separately.  In  B,  pericardium  lying  tlOn  {panes,  H  Wall).  ilie 
around  heart.  H,  heart ;  P.  C.  pericardial  cav-  cavity  of  the  SCrOUS  peri- 
cardium contains  a  small 
quantity  of  serous  liquid. 
Its  contiguous  or  opposed  surfaces  are  lined  by  endothelium  and 
are  very  smooth  and  polished. 

As  the  opposing  surfaces,  owing  to  the  constant  contractions 
of  the  heart,  are  continually  sliding  one  upon  the  other,  they  are 
admirably  constructed  to  protect  the  heart  from  any  loss  of  power 
by  friction. 

Endocardium.  —  The  interior  of  the  heart  is  lined  by  a  delicate, 
smooth  membrane,  called  the  endocardium.  This  pavement 
membrane  (endothelium)  lines  all  the  cavities  of  the  heart,  and  is 
continued  into  the  blood-vessels,  forming  their  innermost  coat. 

The  cavities  of  the  heart.  —  The  heart  is  divided  from  the  base 
to  the  apex,  by  a  fixed  partition,  into  a  right  and  left  half,  fre- 
quently called  right  and  left  heart.  The  two  sides  of  the  heart  have 
no  communication  with  each  other  after  birth.  The  right  always 
contains  venous,  and  the  left  side  arterial,  blood.  Eaclr  half  is 
subdivided  into  two  cavities,  the  upper,  called  auricle  (atrium) ; 
the  lower,  ventricle  (ventriculumj.  If  we  examine  these  cavities, 
we  notice  that  the  muscular  walls  of  the  auricles  are  much  thinner 
than  those  of  the  ventricles,  and  the  wall  of  the  left  ventricle  is 
thicker  than  that  of  the  right.  This  difference  in  bulk  is  to  be 
accounted  for,  as  we  shall  see  later  on,  by  the  greater  amount  of 
work  the  ventricles,  as  compared  with  the  auricles,  have  to  do. 


Chap.  X] 


BLOOD  VASCULAR  SYSTEM 


165 


These  cavities  communicate  with  one  another  by  means  of 
constricted  openings,  the  auriculo-ventricular  orifices,  which  are 
strengthened  by  fibrous  rings  and  protected  by  valves. 

Important  orifices   of  the  heart.  —  Eight   large   blood-vessels 
are  directly  connected  with  the  heart,  hence  there  are  eight  orifices 


Ijcft  pulmonary 


Left  auricula 
appeiiiliv 


__  Anterior  coro- 
nary vesselb 
Dart  pointing  to 
aortic  opening 


Fig.  101. 


Left  Auricle  and  Ventricle,  the  Hind  Wall  of  Each  having 
BEEN  Removed.     (Gerrish.) 


plus  the  two  between  the  auricles  and  ventricles,  making  a  total  of 
ten. 

On  the  right  side  of  the  heart,  the  superior  and  inferior  vena 
cava  empty  into  the  auricle,  and  the  pulmonary  artery  leaves  the 
ventricle. 

On  the  left  side  of  the  heart,  four  pulmonary  veins  empty  into 
the  auricle,  and  the  aorta  leaves  the  ventricle.  There  are  some 
smaller  openings  to  receive  blood  directly  from  the  heart  sub- 
stance, and  before  birth  there  is  an  opening  between  the  right  and 


166 


ANATOMY  FOR  NURSES 


[Chap.  X 


left  auricle  called  the  foramen  ovale.     Normally  this  closes  as  soon 
as  the  infant  })roathes.  "    • 

Valves  of  the  heart.  —  The  auriculo-ventricular  orifices  and  the 

openings  into  the  aorta 
and  pulmonary  artery  are 
guarded  by  valves. 

The  tricuspid  valve.  — 
The  valve  guarding  the 
right  auriculo-ventricular 
opening  is  composed  of 
three  irregular-shaped 

flaps,  or  cusps,  and  hence 
is  named  tricuspid.  The 
flaps  are  mainly  formed  of 
fibrous  tissue  covered  by 
endocardium.  At  their  bases  they  are  continuous  with  one  an- 
other, and  form  a  ring-shaped  membrane  around  the  margin  of 
the  auricular  opening  :  their  pointed  ends  are  directed  downward, 
and  are  attached  by  cords,  the  chordae  tendineae,  to  little  muscu- 


FiG.  102.  —  Cross-sectiux  thkough  both 
Ventricles,  showing  the  Shape  of  their 
Cavities  and  the  Relative  Thickness  of 
their  Walls.     (Gcrrish.) 


Fig.  103.  —  Valves  of  the  Heart  and  Great  Arteries,  viewed  from  Above, 
THE  Auricles  having  been  Removed.     (Gerrish.) 

lar  pillars,  the  papillary  muscles,  provided  in  the  interior  of  the 
ventricles  for  this  purpose. 

The  bicuspid  valve.  —  The  valve  guarding  the  left  auricular 
opening  consists  of  only  two  flaps  or  cusps,  and  is  named  the  bi- 


Chap.  X] 


BLOOD  VASCULAR  SYSTEM 


167 


cuspid,  or  mitral  valve.  It  is  attached  in  the  same  manner  as 
the  triscuspid  valve,  which  it  closely  resembles  in  structure,  except 
that  it  is  much  stronger  and  thicker  in  all  its  parts. 

Function.  —  These  valves  oppose  no  obstacle  to  the  passage  of 
the  blood  from  the  auricles  into  the  ventricles  because  the  free 
edges  of  the  flaps  are  pointed  in  the  direction  of  the  blood  current ; 
but  any  flow  forced  backward  gets  behind  the  flaps  of  the  valve 
(between  the  flap  and  the  wall  of  the  ventricle),  and  drives  the 
flaps  backward  and  upward,  until,  meeting  at  their  edges,  they 


OPENING    OF    RIGHT 
CORONARY   ARTERY 


OPENING    or    LEFT 
CORONARY    ARTERY 


ANTERIOR. 

SEGMENT   CORPUS? 
ARANTII 


RIGHT 
POSTERIOR 
SEGMENT 


LEFT  POSTERIOR 
N  SEGMENT 

FIBROUS  THICKEN- 
ING  OF   EDGE 


Fig.  104.  —  Aortic  Valve.     The  artery  has  been  cut  open  between  the  anterior 
and  left  posterior  segments,  and  spread  out.     (Gerrish.) 


unite  and  form  a  complete  transverse  partition  between  the  ven- 
tricle and  auricle.  Being  retained  by  the  chordae  tendinese,  the 
expanded  flaps  of  the  valve  resist  any  pressure  of  the  blood  which 
might  otherwise  force  them  back  to  open  into  the  auricle;  the 
papillary  muscles,  also,  to  which  the  chordae  tendineae  are  attached, 
contract  and  shorten  at  the  same  time,  and  thus  keep  them  taut. 
Semilunar  valves.  —  The  valves  between  the  ventricles  and 
arteries  are  called  the  semilunar  valves  (aortic  and  pulmonary). 
These  valves  consist  of  three  half-moon-shaped  pockets,  each 
pocket  being  attached  by  its  convex  border  to  the  inside  of  the 
artery  where  it  joins  the  ventricle,  while  its  other  border  projects 
into  the  interior  of  the  vessel.  Small  nodular  bodies,  called  the 
corpora  Arantii,  are  attached  to  the  centre  of  the  free  edge  of  each 
pocket. 


168  ANATOMY  FOR  NURSES  [Chap.  X 

Function.  —  These  valves  offer  no  resistance  to  the  passage  of 
blood  from  the  heart  into  the  arteries,  as  the  free  borders  project 
into  the  arteries,  but  they  form  a  complete  barrier  to  the  passage 
of  blood  in  the  opposite  direction.  In  this  case  each  pocket 
becomes  filled  with  blood,  and  the  free  borders  are  floated  out  and 
distended  so  that  they  meet  in  the  centre  of  the  vessel.  The 
corpora  Arantii  assist  in  the  closure  of  these  valves  and  help  to 
make  the  barrier  perfect. 

The  orifices  of  the  heart  which  serve  for  openings  into  veins 
are  not  protected  by  valves,  with  the  possible  exception  of  the 
opening  into  the  inferior  vena  cava  which  is  partly  covered  by  a 
membrane  known  as  the  Eustachian  valve. 

Blood  Supply.  —  Just  after  the  aorta  leaves  the  left  ventricle  it 
gives  off  two  small  branches,  called  the  right  and  left  coronary 
arteries.  They  encircle  the  heart  like  a  crown,  hence  their  name. 
They  supply  the  substance  of  the  heart  with  blood,  as  the  blood 
contained  within  the  cavities  of  the  heart  only  nourishes  the 
pericardium. 

Nerve  supply.  —  The  heart  is  supplied  (1)  by  the  pneumo-gastric 
nerves  from  the  central  nervous  system  and  (2)  from  the  sympa- 
thetic system.  Stimulation  of  the  pneumo-gastric  fibres  slows  the 
action  of  the  heart.  They  are  therefore  known  as  cardiac  inhibi- 
tors. Stimulation  of  the  sympathetic  fibres  increases  the  force  of 
the  heart  beat,  therefore  they  are  known  as  cardiac  accelerators. 

ARTERIES 

These  are  hollow  vessels  that  lead  from  the  heart  and  are  com- 
posed of  three  coats  :  — 

1.  A  smooth  endothelial  lining. 

2.  A  middle  coat  of  fibrous  elastic  tissue  with  muscle  fibres 
interlaced  and  circularly  disposed  around  vessel. 

3.  An  outer,  dense,  fibrous  coat  with  fibres  arranged  longitudi- 
nally. 

1.  The  inner  lining  or  endothelium  is  continuous  with  the 
endocardium  which  lines  the  heart.  It  furnishes  a  smooth,  slippery 
surface  over  which  the  blood  can  fiow  without  any  friction. 

2.  By  virtue  of  the  structure  of  the  middle  coat,  the  arteries 
are  both  contractile  and  elastic.  It  is  thicker  and  contains  a  larger 
proportion  of  elastic  tissue  in  the  large  arteries.     In  the  smaller 


INNER  COAT 


Chap.  X]  BLOOD  VASCULAR  SYSTEM  169 

arteries  it  is  thinner  and  contains  a  larger  proportion  of  musculai 
tissue.  The  proper  functioning  of  the  arteries  depends  upon 
their  elasticity  and  contractility  and  may  be  demonstrated  by 
the  following  example  :  — 

If  we  tie  a  piece  of  a  large  artery  at  one  end  and  inject  fluid 
into  the  other  end,  the  artery  swells  out  to  a  very  great  extent, 
but  will  return  at  once 
to  its  former  size  when 
the    fluid    is    let    out. 
This  great  elasticity  of     IK  "^^ — outer  coat 

1-1  1  \\m  all ELASTIC  LAYER  )h,id0LE 

the  arteries  adapts  them     ||j^  Jmt^!l°!'7o''*^y!.''^  ''*^"  ^  '^°*^ 

for  receiving  the  addi- 
tional amount  of  blood 
thrown    into    them    at 

each  contraction  of  the  Fig.  105. —  Diagram  of  a  Cross-section  of 

AN   Artery,   showing  the   Composition   of  its 
heart.  Tunics.     (Gerrish.) 

3.  The  strength  of  an 
artery  depends  largely  upon  the  outer  fibrous  coat ;   it  is  far  less 
easily  cut  or  torn  than  the  other  coats,  and  it  serves  to  resist  un- 
due expansion  of  the  vessel. 

The  arteries  do  not  collapse  when  empty,  and  when  an  arten,^  is 
severed  the  orifice  remains  open.  The  muscular  coat,  however, 
contracts  somewhat  in  the  neighborhood  of  the  opening,  and  the 
elastic  fibres  cause  the  artery  to  retract  a  little  within  its  sheath, 
so  as  to  diminish  its  calibre  and  permit  a  blood-clot  to  plug  the 
orifice.  This  property  of  the  severed  artery  is  an  important  factor 
in  the  arrest  of  hemorrhage. 

Blood  and  nerve  supply  of  the  arteries.  —  The  blood  which 
flows  through  the  arteries  nourishes  only  the  inner  coat.  The 
middle  and  outer  coats  are  supplied  with  arteries,  capillaries,  and 
veins,  called  vasa  vasorum,  or  blood-vessels  of  the  blood-vessels. 

The  muscular  tissue  found  in  the  walls  of  the  arteries  is  supplied 
with  nerves  chiefly  from  the  sympathetic  system.  These  nerves 
are  called  vasomotor,  and  are  divided  into  two  sets,  (1)  vaso- 
constrictor, and  (2)  vaso-dilator. 

Stimulation  of  one  set  of  these  nerves  (vaso-constrictor)  causes 
contraction  of  the  muscle-fibres  and  constriction  of  the  arteries; 
stimulation  of  a  second  set  (vaso-dilator)  causes  a  relaxation  of 
the  muscle-fibres,  and  dilatation  of  the  arteries.     The  widening 


170 


ANATOMY  FOR  NURSES 


[Chap.  X 


and  narrowing  of  the  arteries  not  only  affects  the  local  circulation  in 
different  parts  of  the  body,  but  the  amount  of  resistance  they  op- 
pose to  the  arterial  impulse  also  influences  in  some  degree  the 
character  of  the  heart-beat.  The  terra  "  tone  of  the  arteries  "  is 
used  to  express  the  normal  degree  of  contracture  of  the  arterial 
walls. 

Sheaths  of  the  arteries.  —  The  greater  number  of  the  arteries 
are  accompanied  by  a  nerve  and  one  or  two  veins  and  surrounded 
by  a  sheath  of  connective  tissue,  which  helps  to  support  and  hold 
these  structures  in  position. 

Size  of  the  arteries.  —  The  largest  arteries  in  the  body,  the 
aorta  and  pulmonary  artery,  measure  about  one  inch  (28  mm.)  in 
diameter,  at  their  connection  with  the  heart.  These  arteries 
give  oft"  branches,  which  divide  and  subdivide  into  smaller  branches. 
A  branch  of  an  artery  is  always  less  than  the  trunk  from  which  it 
springs,  hence  the  arteries  grow  smaller  as  they  subdivide,  and 
gradually  lose  their  characteristic  structure.  The  smallest  arte- 
ries are  called  arterioles,  and  at  their  distal  ends,  where  only  the 
internal  coat  remains,  the  capillaries  begin. 


CAPILLARIES 

The  capillaries  are  exceedingly  minute  vessels  which  average 
about  2~oVo  of  an  inch  (0.0125  mm.)  in  diameter.     They  connect 

the  arterioles  with  the  venules  (smallest 
veins),  thus  receiving  the  blood  from 
the  arterioles  and  carrying  it  to  the 
venules. 

Structure.  —  The  walls  of  the  capil- 
laries are  formed  entirely  of  07ie  layer 
of  simple  endothelium  composed  of  flat- 
tened cells  joined  edge  to  edge  by 
cement  substance,  and  continuous  with 
the  laver  which  lines  the  arteries  and 


veins. 

Distribution.  —  The  capillaries  com- 
municate freely  with  one  another  and 
form  interlacing  networks  of  variable 
form  and  size  in  the  different  tissues.  All  the  tissues,  with  the 
exception  of  the  cartilages,  hair,  nails,  cuticle,  and  cornea  of  the 


Fig.  106.  —  Fine  Capil- 
laries FROM  THE  Mesentery 
(Collins.) 


Chap.  X] 


BLOOD  VASCULAR  SYSTEM 


171 


eye/  are  traversed  by  these  networks  of  capillary  vessels.  Their 
diameter  is  so  small  that  the  blood-corpuscles  must  pass  through 
them  in  single  file  and  very  frequently  the  corpuscle  is  bigger  than 
the  calibre  of  the  vessel,  and  has  to  be  squeezed  to  enable  it  to  pass 
through.  In  many  parts  they  lie  so  closely  together  that  a  pin's 
point  cannot  be  inserted  between  them.  They  are  most  abundant, 
and  form  the  finest  networks,  in  those  organs  where  the  blood  is 
needed  for  other  purposes  than  local  nutrition,  such  as,  for  example, 
secretion  or  absorption. 

Function.  In  the  glandular  organs  the  capillaries  supply  the 
substances  requisite  for  secretion  ;  in  the  alimentary  canal  they 
take  up  some  of  the  elements  of  digested  food ;  in  the  lungs  they 
absorb  oxj^gen  and  give  up  carbon  dioxide ;  in  the  kidneys  they 
discharge  the  w^aste  products  collected  from  other  parts ;  all  the 
time,  everywhere  through  their  walls,  that  interchange  is  going 
on  which  is  essential  to  the  renovation  and  life  of  the  whole  body. 
It  is  in  the  capillaries,  then,  that  the  chief  work  of  the  blood  is 
done ;  and  the  object  of  the  vascular 
mechanism  is  to  cause  the  blood  to 
flow  through  these  vessels  in  the  man- 
ner best  adapted  for  accomplishing 
this  work. 

VEINS 
The  veins  have  three  coats  and  on 
the  whole  resemble  the  arteries  in 
structure.  They  differ  from  them  in 
having:  (1)  much  thinner  walls  (see 
Fig.  107) ;  (2)  they  contain  less  elastic 
tissue,  more  white  fibrous  tissue,  and 
because  of  this  are  not  so  elastic  or 
contractile  as  the  arteries  ;  (3)  many 
of  the  veins  are  provided  with  valves. 
Valves.  —  The  valves  are  semilu- 
nar folds  of  the  internal  coat  of  the 
veins ;  and  usually  consist  of  two 
flaps,  rarely  one  or  three. 

The  convex  border  is  attached  to 


w 


Fig.  107.    Th.\xsvkrse  Section' 
THROUGH  A  Sm.\ll  Artery .\ND  Veix, 

SHOWING  THE  ReL.^TIVE  DiFFER- 
EXCE  IN  THE    THICKNESS    OF   THEIR 

W.\LLS.  In  the  vein  (T-O  the  outer 
coat  is  thickest,  in  the  artery  (A)  the 
contractiJe  and  elastic  middle  coat  is 
thickest.     (Klein  and  Noble  Smith.) 

^  These  parts  not  penetrated  by  the  blood-vessels  imbibe  nutritive  matter  from 
adjacent  tissues,  and  are  just  as  dependent  on  the  blood  as  all  the  other  tissues. 


172 


ANATOMY  FOR  NURSES 


[Chap.  X 


the  side  of  the  vein,  and  the  free  edge  points  toward  the  heart. 
Their  function  is  to  keep  the  blood  flowing  in  the  right  direction, 
i.e.  toward  the  heart,  and  prevent  regurgitation. 

Should  the  blood  on  its  onward  course  toward  the  heart  be  for 
any  reason  driven  backward,  the  refluent  blood,  getting  behind 
the  wall  of  the  vein  and  the  flaps  of  the  valve,  will  press  them 
inward  until  their  edges  meet  in  the  middle 
of  the  channel  and  close  it  up. 

The  valves  are  most  numerous  in  the 
veins  where  regurgitation  is  most  likely  to 
occur,  i.e.  the  veins  of  the  extremities.  For 
the  same  reason  a  greater  number  are  found 
in  the  lower  than  in  the  upper  limbs.  They 
are  absent  in  many  of  the  small  veins,  in 
the  large  veins  of  the  trunk,  and  in  veins  not 
subjected  to  muscular  pressure.  The  veins, 
like  the  arteries,  are  supplied  with  both 
blood-vessels  and  nerves ;  the  supply,  how- 
ever, is  far  less  abundant. 

It  must  be  remembered  that  although  the 
arteries,  capillaries,  and  veins  have  each  the 
distinctive  structure  above  described,  it  is  at  the  same  time  diffi- 
cult to  draw  the  line  between  the  smaller  artery  and  larger  capil- 
lary; and  between  the  larger  capillary  and  smaller  vein.  The 
veins  on  leaving  the  capillary  networks  only  gradually  assume 
their  several  coats,  while  the  arteries  dispense  with  their  coats  in 
the  same  imperceptible  way  as  they  approach  the  capillaries. 


Fiu.  108.  —  Diagram 
SHOWING  Valves  of 
Veins.  A,  part  of  a  vein, 
laid  open,  with  two  pairs 
of  valves  ;  B,  longitudinal 
section  of  vein,  showing 
valves  closed.    (Sharpey.) 


LYMPH  VASCULAR  SYSTEM 

As  the  process  of  transudation  described  on  page  153  is  con- 
tinual, it  follows  that  oedema  would  result  from  the  accumulation 
of  lymph  if  some  system  of  drainage  were  not  provided.  This 
drainage  system  is  provided  by  the  lymph  vascular  system. 

Lymph  spaces 


Lymph  Vascular 
System 


Lymph  vessels     < 


Lymph  nodes 


LjTiiph  capillaries. 

L\Tiiphatics. 

Thoracic  duct. 

Right  hanphatic  duct. 

Lacteals. 

Serous  sacs. 


Fig.  109.  —  The  Regions  whose  Lv.mph  flows  into  the  Right  Lymphatic 
Duct  are  suggested  by  the  Red  Area;  those  which  are  tributary  to 
THE  Thoracic  Duct  by  the  Blue  Area.      (Gerrish.) 

173 


174 


ANATOMY  FOR  NURSES 


[Chap.  X 


Lymph  Spaces.  —  The  minute  irregular  spaces  which  exist 
between  the  cells  of  which  the  tissues  are  composed  are  called 
lymph  spaces.  They  are  filled  with  lymph,  and  in  them  the 
lymphatics  begin. 

Lymph  vessels.  —  The  plan  upon  which  the  lymphatic  system 
is  constructed  is  similar  to  that  of  the  blood  vascular  system, 
if  we  omit  the  heart  and  the  arteries.  In  the  lymph  spaces  we 
find  the  closed  ends  of  minute  microscopic  vessels,  called  lymph 
capillaries,  which  are  comparable  to,  but  somewhat  larger  than, 
the  blood  capillaries.  These  lymph  capillaries  unite  to  form 
larger  vessels  called  lymphatics,  which  are  comparable  to  the  veins. 
The  lymphatics  continue  to  unite  and  form  larger  and  larger 
vessels  until  finally  they  converge  into  two  main  channels,  (1)  the 
thoracic  duct,  and  (2)  the  right  lymphatic  duct. 

The  thoracic  duct.  —  The  thoracic  duct  begins  at  the  second 
lumbar  vertebra  and  ascends  upward  to  the  seventh  cervical. 
It  lies  in  front  of  the  bodies  of  the  vertebrje,  gradually  inclining 
towards  the  left,  until,  when  on  a  level  with 
the  seventh  cervical  vertebra,  it  turns  outward 
and  arches  downward  and  forward  to  termi- 
nate in  the  innominate  vein  at  the  point  of 
junction  of  the  left  internal  jugular  and  left 
subclavian. 

It  is  from  fifteen  to  eighteen  inches  (375-450 
mm.)  long  in  the  adult,  and  is  about  the  size 
of  a  goose  quill.  It  receives  the  lymph  from 
the  left  side  of  the  head,  neck,  and  chest,  all  of 
the  abdomen  and  both  lower  limbs,  also  the 
chyle  from  the  lacteals.  It  is  dilated  below, 
where  it  receives  the  lymphatics  from  the  lower 
limbs  and  the  chyle  from  the  lacteals,  the  dil- 
atation being  known  as  the  chyle  cistern  (re- 
ceptaculum  chyli).     (See  Fig.  135.) 

The  right  lymphatic  duct.  —  The  right  lym- 
phatic duct  is  a  short  vessel,  usually  from  one 
to  one  and  one-half  inches  (25  to  38  mm.)  in 
length.     It  pours  its  contents   into   the   in- 
nominate vein  at  the  junction  of  the  right  internal  jugular  and 
subclavian  veins. 


Fig.  110. — V.\LVES  OF 
THE  Lymphatics. 


Chap.  X] 


LYMPH  VASCULAR  SYSTEM 


175 


The  lymphatics  from  the  right  side  of  the  head,  neck,  the  right 
arm,  and  the  upper  part  of  the  trunk  enter  the  right  lymphatic 
duct.     The  parts    drained   by   each  are  suggested    by  Fig.  109. 

Structure  of  the  lymph  vessels.  —  The  lymphatics  resemble  the 
veins  in  their  structure  as  well  as  in  their  arrangement.  The 
smallest  have  but  a  single  coat 
of  endothelioid  cells,  having  a 
peculiar  dentated  outline.  The 
larger  vessels  have  three  coats, 
similar  to  veins,  except  that 
they  are  so  thin  as  to  be  trans- 
parent, and  they  are  more  abun- 
dantly supplied  with  valves. 
The  valves  are  constructed  and 
arranged  in  the  same  fashion  as 
those  of  the  veins,  but  follow 
one  another  at  such  short  inter- 
vals, that,  when  distended,  they 
give  the  vessel  a  beaded  or 
jointed  appearance.  They  are 
usually  wanting  in  the  smaller 
networks.  The  valves  allow  the 
passage  of  material  from  the 
smaller  to  the  larger  lymphatics, 
and  from  these  into  the  veins, 
and  obstruct  the  flow  of  any- 
thing in  the  opposite  direction. 

Classification  of  lymphatics. 
—  The  lymph,  like  the  blood  in 
the  veins,  is  returned  from  the 
limbs  and  viscera  by  a  deep  and 
by  a  superficial  set  of  vessels. 
The  deep  lymphatics  accom- 
pany the  large  blood-vessels, 
and  the  superficial  are  distributed  through  the  subcutaneous  areo- 
lar tissue.  There  is  no  communication  between  these  two  sets  of 
vessels,  but  each  set  forms  frequent  anastomoses. 

Lacteals.  —  The  lymphatics  that  have  their  origin  in  the  villi  of 
the  small  intestine  are  called  lacteals.     During  the  period  of  in- 


FiG.  111.  —  Lacteals  a.nd  Lymphatics, 
DURING   Digestion.     (Dalton.) 


176 


ANATOMY  FOR  NURSES 


[ClL\P.  X 


very  little  from 
in    the    ordinary 


testinal  digestion  they  are  filled  with  chyle  which  has  a  white 
aspect,  dependent  upon  the  fatty  particles  absorbed  from  the 
food,  and  suspended  in  it  like  oil  globules  in  milk.  After  fast- 
ing, the  lacteals  contain  lymph  which  differs 

the    lymph    found 
lymphatics. 

Serous  sacs.  —  A  close  relationship 
exists  between  the  lymphatics  and 
the  serous  membranes  proper.  These 
closed  sacs  are  to  be  regarded  as 
prodigiously  expanded  lymph  spaces. 
The  true  stomata  of  these  serous  mem- 
branes are  connected  with  other  lymph 
spaces. 

Function  of  the  lymphatics.  —  The 
function  of  the  lymphatics  is  to  carry 
from  the  tissues  to  the  veins  all  the 
materials  which  the  tissues  do  not 
need.  Functionally  they  may  be  con- 
sidered between  the  capillaries  and  the 
veins,  as  they  gather  up  the  lymph 
which  exudes  through  the  thin  capil- 
lary walls,  and  return  it  to  the  innomi- 
nate veins.  Here  it  becomes  mixed 
with  the  blood,  enters  the  superior 
vena  cava,  and  then  the  right  auricle 
of  the  heart.  The  function  of  the  lacteals  is  to  help  in  the  ab- 
sorption of  digested  food,  especially  fats. 

Lymph  nodes.  —  The  lymph  nodes  are  numerous  round  or 
ovoid  bodies  placed  in  the  course  of  the  lymphatics.  They  vary 
in  size  from  a  pinhead  to  an  almond.  A  lymph  node  is  covered  by 
an  envelope,  or  capsule,  of  connective  and  muscular  tissue.  This 
capsule  sends  fibrous  bands  called  trabeculae  (little  beams) 
into  the  substance  of  the  node,  and  divides  it  into  irregular  spaces, 
which  communicate  freely  with  each  other.  The  irregular  spaces 
are  occupied  by  a  mass  of  cellular  pulp  substance,  which,  however, 
does  not  quite  fill  them  as  it  never  touches  the  capsule  or  trabeculae, 
but  leaves  a  narrow  interval  between  itself  and  them.  It  looks  as  if 
the  pulp  had  originally  filled  the  framework  and  then  shrunk  away 


Fig.  112. — A  Lymph  Node 
WITH  ITS  Afferent  and  Effer- 
ent Vessels.     (Gerrish.) 


Chap.  X]  LYMPH  VASCULAR  SYSTEM 


177 


slightly  on  all  sides.  The  spaces  thus  left  form  channels  for  the 
passage  of  the  lymph,  which  enters  by  afferent  vessels,  and,  after 
circulating  through  the  node,  issues  by  efferent  vessels.  Lymph 
nodes  are  well  supplied  with  blood.     A  lymph  node  is  comparable 


DEEP  CERVICAL   NODE 


wu 


%-z~~^ 


—  PROPER   AXILLARY 
NODES 


EPICONDYLAR   NODC 


PALMAR    PLEXUS 


Fig.  113.  —  The  Lymph  Nodes  and  Vessels  of  the  Upper  Limb.     (Gerrish.) 

N 


178 


ANATOMY  FOR  NURSES 


[Chap.  X 


n 


w 


^ . 


^ 


^ 


%. 


r\^ 


■•/ 


Fig.  114.  —  The  Lymph 
Nodes  and  Vessels  of  the 
Lower  Limb.     (Gerrish.) 


to  a  sponge  placed  in  a  snugly  fitting 
rubber  bag.  The  rubber  bag  connects 
on  one  side  with  a  rubber  tube  repre- 
senting the  afferent  lymph  vessel,  and 
from  the  opposite  side  there  leads  away 
from  the  rubber  bag  another  tube  repre- 
senting the  efferent  lymph  vessel.  The 
rubber  bag  is  the  representative  of  the 
capsule  of  the  node,  the  meshwork  of 
the  sponge  is  comparable  to  the  frame- 
work of  the  node,  and  the  holes  in 
the  sponge  to  the  open  channels.  The 
substance  of  a  lymph  node  is  reticular 
adenoid  tissue. 

Location  of  nodes.  —  Lymph  nodes 
are  found  in  great  numbers  in  the  neck, 
thorax,  axilla,  groin,  mesentery  and 
alongside  of  the  aorta,  vena  cava  in- 
ferior, and  the  iliac  vessels.  A  few  are 
found  in  the  popliteal  space  and  in 
the  arm  as  far  as  the  elbow,  but  none 
farther  down  the  leg  or  forearm.  They 
are  usually  named  from  the  position 
in  which  they  are  found  in  the  body, 
viz.  cervical  in  the  neck,  thoracic  in 
the  thorax,  axillary  in  the  axilla,  ingui- 
nal in  the  groin,  mesenteric  in  the 
mesentery. 

Function  of  the  lymph  nodes.  — 
The  lymph  nodes  serve  two  important 
purposes :  — 

(1)  As  filters  for  the  lymph.  —  In 
this  way  they  act  as  safety-valves 
and  serve  to  retard  the  spread  of 
infection  through  the  body.  If  any 
portion  of  the  body  is  infected,  the 
poison  may  be  carried  by  the  lym- 
phatics to  their  special  nodes.  There  its 
course  is  stopped  and  the  node  may 
suffer  enlargement  or  even  break  down 


Chap.  X] 


LYMPH  VASCULAR  SYSTEM 


179 


and  be  destroyed.     If  the  infection  is  not  arrested,  the  node  next 
in  line  will  suffer,  then  the  next,  and  so  on. 


Fig.  115.  —  The  Lymph  Nodes  of  the  Neck  and  Upper  Part  of  the  Thorax. 

(Gerrish.) 

(2)  Multiplication  of  leucocytes.  —  In  its  passage  through  the 
node  the  lymph  takes  up  fresh  leucocytes,  which  are  continually 
multiplying  by  cell  division  in  the  glandular  substance. 


180 


ANATOMY  FOR  NURSES 


[ClL\P.  X 


Blood  Vascular 
System 


Location 


Structure 


Cavities 


Orifices 


SUMMARY 

Heart. 

Arteries  —  small  arteries  are  named  arterioles. 

Capillaries. 

^'eins  —  small  veins  are  named  venules. 

(Between  lungs. 
Behind  sternum. 
Above  diaphragm. 

'  Smooth  lining  on  inside  —  Endocardium. 
Muscle  substance  —  Myocardium. 

I  Fibrous  portion. 
„  j  Yisceral. 

1  Parietal. 
j  Receives  blood. 
1  Thin  walls. 

r  Expels  blood.         Pulmonary 
<      artcn.'. 
[  Thick  walls. 
Left  j  Receives  blood. 

auricle    \  Thin  walls. 
Left    ven-  (  Expels  blood.     Aorta, 
tricle       \  Yery  thick  walls. 

'  Superior  vena  cava  —  returns 
blood  from  upper  portion  of 
Right  body. 

auricle       Inferior  vena  cava  —  returns 
Right        J  blood  from  lower  portion  of 

heart     1  [      body. 

Auiiculo-ventricular  orifice   between    au- 
ricle and  ventricle. 
Right  ven-  j  Pulmonary     artery  —  carries 
tricle       1      blood  from  heart  to  lungs. 


Right 
heart 


Left 
heart 


Right 
auricle 

Right  ven- 
tricle 


■ 

Two  right  pulmo- 

Return 

Left 

nary  veins 

blood 

auricle 

Two  left  pulmo- 

from 

Left 

nary  veins 

lungs. 

heart 

Auriculo-ventricular  orifice  between  auri- 

cle and  ventricle. 

Left    ven-  f  Aorta  —  distributes  blood  to 

tricle 

^  all  parts  of  body. 

Chap.  X] 


LYMPH  VASCULAR  SYSTEM 


181 


Valves 


Semilunar 
valves 


Nerve  Supply 


Blood  Supply 


Coats , 


2.  Muscular  and  elastic  tissue 


Tricuspid  valve  —  composed  of  three  cusps  situated 

in  the  right  ventricle. 
Bicuspid  or  mitral  valve  —  composed  of  two  strong, 
thick  cusps  situated  in  the  left  ventricle. 
f  Aortic  —  composed  of  three  half-moon- 
I  shaped     pockets     between 

aorta  and  left  ventricle. 
Pulmonary  —  composed   of    three    half- 
moon-shaped    pockets    be- 
tween    pulmonarj^     artery 
and  right  ventricle. 
Central    nervous    system  —  Pneumogastric    nerves, 

inhibitory  fibres,  slow  the  heart. 
Sympathetic    system  —  Accelerator    fibres     increase 
rapidity  and  force  of  heart. 

Right  coronary  artery  ]  ,         ,       . 

J  f,  X  }  branches  from  aorta. 

Lett  coronary  artery     j 

Hollow  tubes  —  Carry  blood  from  heart. 
1.  Endothelial  lining. 

contractile     and 
elastic. 
,  3.  Fibrous  tissue. 
Sheaths  —  outside  covering  of  connective  tissue  which  sur- 
rounds the  arteries. 
Size  —  Aorta  about  one  inch  in  diameter.     Arteries  grow 
smaller   as   they    subdivide.     Smallest    ones   are 
microscopic  and  are  called  arterioles. 
Tmy  tubes  —  about  Woo  of  an  inch  in  diameter.     Connect 

arterioles  and  venules. 
One  coat  of  simple  endothelium. 
.  Communicate  freely  —  form  networks. 
Collapsible  tubes  —  smallest  ones,  called  venules,  begin  where 

capillaries  end. 
Carry  blood  to  heart. 
Three  coats,  same  as  arteries  but  thinner. 
Less  elastic  and  contractile. 
,  Valves.     1-2-3  semilunar  pockets. 

Vaso  vasorum  —  Term  appUed  to  blood-vessels  that  are  supplied  to  coats 

of  other  blood-vessels. 
Vasomotor  —  Term  applied  to  nerves  supphed  to    (  Vaso-constrictor. 
blood-vessels  —  2  sets  I  Vaso-dilator. 


Arteries 


Capillaries 


Vfeins 


182 


ANATOMY  FOR  NURSES 


[Chap.  X 


Lymph 
Vascular 
System 


Lymph  spaces 


Lymph  vessels 


Lymph  nodes 


Lymph  capillaries. 

LjTnphatics. 

Thoracic  duct. 

Right  hnnphatic  duct. 

Lacteals. 

Serous  sacs. 


Lymph  Spaces  —  Irregular  spaces  between  cells  of  which  tissues  are  com- 
posed. 


Lymph  Vessels 


Lymph 
Capillaries 


Thoracic  Duct  < 


Origin  in  lymph  spaces. 

One  coat  of  endothelium  —  dentated. 

Start  as  microscopic  hanph  capillaries, 
unite  to  form  lymphatics.     Compar- 
able to  formation  of  veins. 
Lymphatics  —  three  coats  —  numerous  valves. 

15  to  18  in.  long.     Size  of  goose-quill. 

In  front  of  vertebra  from  2d  lumbar  to 
7th  cervical. 

Has  three  coats  —  numerous  valves. 

Dilatation  at  lower  portion  called  chyle 
cistern. 

Receives  lymph  from  left  side  of  head, 
neck,  and  chest,  left  arm,  all  of  abdo- 
men, and  both  lower  limbs.  Receives 
chyle  from  lacteals. 

Pours  Ij-mph  and  chyle  into  left  innomi- 
nate vein. 
j  1  to  1|  in.  long. 

j  Receives  lymph  from  right  side  of  head, 
I      neck,  and  chest,  also  right  arm. 

Pours  l3^nph  into  right  innominate  vein. 

Deep  —  accompanj'-  large  blood-vessels. 

Superficial  —  distributed   through    the 
subcutaneous  areolar  tissue. 

L5Tnphatics  of  the  intestines. 

Many  originate  in  ^^lli  of  small  intestine. 

Contain  (  ^"^^"S  digestion  —  chyle. 
I  During  fasting  —  lymph. 
Absorb  fatty  substances. 
)  Expanded  IjTiiph  spaces. 
j  Communicate  by  means  of  stomata  with 
[      other  IjTTiph  spaces. 
Function  —  Drain  off  IjTnph  from  all  parts  of  the  body 
and  return  it  to  the  innominate  veins. 


Right  Lym- 
phatic Duct 


Classification 


Lacteals 


Serous  Sacs 


Chap.  X] 


LYMPH  VASCULAR  SYSTEM 


183 


Description 


Lymph  Nodes    < 


Location 


Function 


Shape 


Round. 
Ovoid. 

Size  varies  from  pinhead  to  almond. 
Connective 


Consists  of  outer  capsule 


into 


and 

muscular 
tissue, 
irregular   spaces 


Interior  divided 
like  sponge. 

Spaces  partially  ^iUed  with  reticular 
adenoid  tissue.  Communicating 
channels  for  lymph,  which  enters  by 
afferent,  leaves  by  efferent,  vessels. 

Are  well  supplied  with  blood. 

Neck,  thorax,  axilla,  groin,  mesentery. 

Alongside  of  great  vessels  of  trunk. 

In  the  arms  as  far  as  elbows. 

In  the  legs  as  far  as  popliteal  space. 

Usually  name  indicates  location. 

1.  Filters  —  preventive  and  protective. 

2.  Multiplication  of  leucocytes. 


CHAPTER    XI 

THE  VASCULAR  SYSTEM  CONTINUED:  ARTERIES;  PULMONARY 
SYSTEM;  GENERAL  SYSTEM;  VEINS;  SUPPLEMENTARY 
CHANNEL,    AND    PORTAL    SYSTEM 


ARTERIES 

The  arteries,  which  carry  and  regulate  the  supply  of  blood  from 
the  heart  to  the  capillaries,  are  distributed  throughout  the  body 
i^  a  systematic  manner,  and  before  taking  up  the  circulation,  we 


ANASTOMOSIS 


ECURTIENT 
BRANCH 


Fig.  116.  —  Diagram  showing  the  Branchings,  Anastomoses,  and  Conflu- 
ence OF  Arteries.     (Gerrish.) 

must  try  to  gain  a  general  idea  of  this  system  of  distribution,  in 
order  that  we  may  be  able  to  locate  the  position  of  these  important 
vessels.  The  arteries  usually  occupy  protected  situations,  that  they 
may  be  exposed  as  little  as  possible  to  accidental  injury,  or  to  the 
effects  of  local  pressure. 

184     . 


Chap.  XI]  THE  VASCULAR   SYSTEM  185 

Division.  —  As  they  proceed  in  their  course  they  divide  into 
branches,  the  division  taking  place  in  different  ways. 

(1)  An  artery  may  at  once  resolve  itself  into  two  branches  of 
nearly  equal  size  (dichotomous,  division,  or  splitting  in  two). 

(2)  It  may  give  off  several  branches  in  succession  and  still 
maintain  its  character  as  a  trunk. 

(3)  It  may  give  off  one  branch  that  divides  into  three  equal 
branches.  In  this  case  the  parent  branch  is  called  an  axis. 
Example  —  coeliac  axis. 

Anastomosis  or  Inosculation.  —  The  distal  ends  of  arteries  unite 
at  frequent  intervals,  when  they  are  said  to  anastomose,  or  inoscu- 
late. Such  inosculations  admit  of  free  communication  between 
the  currents  of  the  blood,  tend  to  promote  equality  of  distribution 
and  of  pressure,  and  to  obviate  the  effects  of  local  interruption. 
It  is  this  arrangement  which  allows  of  the  ligating  of  veins  and 
arteries  during  operations,  or  after  injuries,  without  serious  inter- 
ference with  the  circulation  in  the  part. 

Plexus.  —  When  a  number  of  arteries  form  many  inosculations 
within  a  limited  area,  it  is  described  as  a  plexus  or  network. 
Arteries  commonly  pursue  a  tolerably  straight  course,  but  in 
some  parts  of  the  body  they  are  tortuous.  The  facial  artery,  in  its 
course  over  the  face,  and  the  arteries  of  the  lips  are  extremely 
tortuous,  so  that  they  may  accommodate  themselves  to  the 
movements  of  the  parts. 

Divisions  of  the  vascular  system.  —  The  blood-vessels  of  the 
body  are  arranged  in  two  main  systems,  namely,  the  pulmonary 
and  the  general  or  systemic. 

The  pulmonary  system.  —  This  is  the  lesser  system  and  pro- 
vides for  the  circulation  of  blood  from  the  right  ventricle  to  the 
lungs,  and  then  back  to  the  left  auricle.  This  is  called  the  pul- 
monary circulation. 

Blood-vessels  of  the  pulmonary  system.  —  The  blood-vessels 
of  the  pulmonary  system  are  (1)  the  pulmonary  artery  and  all  its 
branches,  (2)  the  capillaries  which  connect  these  branches  with  the 
veins,  and  (3)  the  pulmonary  veins. 

The  pulmonary  artery.  —  The  pulmonary  artery  conveys  the 
dark  blood  from  the  right  side  of  the  heart  to  the  lungs.  The  main 
trunk  is  a  short,  wide  vessel  (diameter  about  one  inch,  or  30  mm.) 
which  arises  from  the  right  ventricle  and  runs  for  a  distance  of 


186 


ANATOMY  FOR   NURSES 


[Chap.  XI 


two  inches  (50  mm.)  upward,  backward,  and  to  the  left.     Between 
the  fifth  and  sixth  thoracic  vertebrae  it  divides  into  two  branches, 


Inoomioate 


Temporal 

Ejttcmal  drotid 
Common  carolid 
Subdaviao 
Aorta 


Axillary 


brachial 


Fig.  117.  —  The  Principal  Arteries  of  the  Body.     (Morrow.) 

the  right  and  left  pulmonary  arteries  which  pass  to  the  right  and 
left  lungs.  (See  Fig.  99.)  From  these  main  branches,  arteries 
arise  which  divide  and  subdivide,  grow  smaller  in  size,  and  finally 
merge  into  capillaries.     These  capillaries  unite,  grow  larger  in  size, 


Chap.  XI] 


THE  VASCULAR  SYSTEM 


187 


and  gradually  assume  the  characteristics  of    veins.     The  veins 
unite  to  form  the  pulmonary  veins. 

The  pulmonary  veins.  —  The  pulmonary  veins  are  four  short 
trunks  which  convey  the  oxidized  blood  from  the  lungs  to  the 
left  auricle,  and  which  are  found,  tw^o  on  each  side,  —  in  the 


Entrance  of 
,vena  azygos 

Branch  of  pul- 
monary artery 


Fig.  118.  —  Pulmonary  Veins,  seen  in  a  Dorsal  View  of  the  Heart  and 
Lungs.  The  left  lung  is  pulled  to  the  left,  and  the  right  lung  has  been  partly  cut 
away  to  show  the  ramifications  of  the  air-tubes  and  blood-vessels.      (Gerrish.) 

root  of  the  corresponding  lung.  The  pulmonary  veins  have  no 
valves. 

The  general  system.  —  This  is  the  larger  system  and  provides 
for  the  circulation  of  blood  from  the  left  ventricle  to  all  parts 
of  the  body  by  means  of  the  aorta  and  its  branches,  and  the  return 
to  the  right  auricle  by  means  of  the  vense  cavse.  This  is  called  the 
systemic  circulation. 

The  blood-vessels  of  the  general  system.  —  The  blood-vessels 
of  the  general  system  consist  of  (1)  the  aorta,  and  all  the  arteries 
that  originate  from  it,  (2)  the  capillaries  which  connect  the 
arteries  and  veins,  and  (3)  all  the  veins  of  the  body  which  empty 


188 


ANATOMY  FOR  NURSES 


[Chap.  XI 


either  directly  into  the  heart,  or  indirectly  by  means  of  the  superior 

and  inferior  venie  cavae. 

The  aorta. —  Tiie  aorta  is  the  main  trunk  of  the  arterial  system. 

Springing  from  the  left  ventricle  of  the  heart,  it  arches  over  the 

root  of  the  left  lung,  de- 
scends along  the  verte- 
bral column,  and  after 
passing  through  the  dia- 
phragm into  the  abdom- 
inal cavity,  ends  opposite 
the  fourth  lumbar  verte- 
bra by  dividing  into  the 
right  and  left  common 
iliac  arteries.  In  this 
course  the  aorta  forms  a 
continuous  single  trunk, 
which  gradually  dimin- 
ishes in  size  from  its 
commencement  to  its 
termination  (from  28  to 
17  mm.)  and  gives  off 
larger  or  smaller  branches 
at  various  points. 

It  may  be  divided  as 
follows :  — 

(1)  The  ascending 
aorta  is  the  short  part 
which  is  contained  within 
the  pericardium. 

(2)  The  arch  is  the 
part  extending  from  the 
ascending  aorta  and 
forming     a    well-marked 

curve  in  front  of  the  trachea,  and  around  the  root  of  the  left 
lung  to  the  border  of  the  fourth  thoracic  vertebra. 

(3)  The  descending  thoracic  aorta  is  the  comparatively  straight 
part  that  extends  from  the  lower  border  of  the  fourth  thoracic 
vertebra  on  the  left  side,  to  the  opening  in  the  diaphragm  below 
the  last  thoracic  vertebra.  It  has  a  length  of  from  seven  to  eight 
inches  (175  to  200  mm.). 


Fig.  119.  —  Thor.\cic  Aort.\.     (Gerrish.) 


Chap.  XI]  THE  VASCULAR  SYSTEM 


189 


(4)  The  abdominal  aorta  commences  about  the  lower  border  of 
the  last  thoracic  vertebra,  and  terminates  below  by  dividing  into 


Phrenic 


A  lumbar  vein 


Fig.  120.  —  Abdominal  Aorta.     (Gerrish.) 


the  two  common  iliac  arteries.  The  bifurcation  usually  takes 
place  about  halfway  down  the  body  of  the  fourth  lumbar  vertebra, 
which  corresponds  to  a  spot  on  the  front  of  the  abdomen,  slightly 


190 


ANATOMY  FOR  NURSES 


[Chap.  XI 


below  and  to  the  left  of  the  umbilicus.     Its  length  is  about  five 
inches  (125  mm.). 

The  important  branches  arising  from  the  aorta  may  be  outlined 

as  follows :  — 

Ascending  Aorta  —  Coronary  arteries. 

C  Innominate. 
Arch  of  Aorta       \  Left  common  carotid. 
I  Left  subclavian. 
Intercostal. 
Pericardial. 
Thoracic  Aorta     I  Bronchial. 

(Esophageal. 
.  Posterior  mediastinal. 

Cceliac  axis. 


Aorta  < 


Abdominal  Aorta 


Superior  mesenteric. 
Inferior  mesenteric. 
Visceral  group  <  Renal  arteries. 
Supra-renal. 
Spermatic. 
^  Ovarian. 

I  Phrenic. 
Lumbar. 
Middle  sacral. 


The  coronary  arteries.  —  The  right  and  left  coronary  arteries 
arise  from  the  aorta  immediately  above  the  semilunar  valves. 
(See  Fig.  10-1.)  They  encircle  the  heart  and  give  off  numerous 
branches  that  supply  the  substance  of  the  heart. 

Innominate.  —  The  innominate  (brachio-cephalic)  artery  arises 
from  the  right  upper  surface  of  the  arch,  ascends  obliquely  toward 
the  right,  until,  arriving  on  a  level  with  the  upper  margin  of  the 
clavicle,  it  divides  into  the  right  common  carotid  and  right  sub- 
clavian arteries.  Its  usual  length  is  from  one  to  two  inches  (25  to 
50  mm.). 

The  common  carotid  arteries.  —  The  left  common  carotid 
arises  from  the  middle  of  the  upper  surface  of  the  arch  of  the 
aorta,  and  the  right  common  carotid  arises  at  the  division  of  the 
innominate,  consequently  the  left  carotid  is  an  inch  or  two  longer 
than  the  right.  They  ascend  obliquely  on  either  side  of  the  neck 
until,  on  a  level  with  the  upper  border  of  the  laryngeal  prominence 
(Adam's  apple),  they  divide  into  two  great  branches:     (1)  the 


Chap.  XI] 


THE  VASCULAR  SYSTEM 


191 


external  carotid,  (2)  the  internal  carotid.  At  the  root  of  the  neck 
the  common  carotids  are  separated  from  each  other  by  only  a 
narrow  interval,  corresponding  with  the  width  of  the  trachea ; 
but  as  they  ascend  they  are  separated  by  a  much  larger  interval, 
corresponding  with  the  breadth  of  the  larynx  and  pharynx. 

Each  external  carotid  has  eight  branches,  which  are  distributed 
to  the  throat,  tongue,  face,  ears,  and  walls  of  the  cranium. 


Fig.  121.  —  Subclavian  and  Axillary  Arteries.     (Gerrish.) 

Each  internal  carotid  has  many  branches  which  are  distributed 
to  the  brain  and  eyes.  The  chief  ones  are  the  cerebral  and 
ophthalmic. 

Circle  of  Willis.  — The  circle  of  Willis  is  a  remarkable  anastomosis 
formed  by  the  blood-vessels  of  the  brain.  It  is  situated  at  the  base 
of  the  brain  and  is  formed  by  the  union  of  (1)  the  anterior  and 
posterior  cerebral  arteries,  which  are  branches  of  the  internal 
carotid,  and  (2)  branches  of  the  basilar  artery,  which  is  formed  by 


192 


ANATOMY   FOR   NURSES 


[Chap.  XI 


the  union  of  the  two  vertebrals.^  These  arteries  are  joined  in  such 
a  manner  as  to  form  a  complete  circle,  and  this  arrangement 
serves  (1)  to  equalize  the  circulation  of  the  blood  in  the  brain, 

and  (2)  in  case  of  destruction  of  one 
of  the  arteries,  it  provides  for  the 
blood  reaching  the  brain  through 
other  vessels. 

The  subclavian  arteries.  —  The 
right  subclavian  arises  at  the  divi- 
sion of  the  innominate,  and  the  left 
subclavian  from  the  arch  of  the 
aorta.  The  subclavian  arteries  are 
the  first  portions  of  a  long  trunk 
which  forms  the  main  artery  of  the 
upper  limb,  and  which  is  artificially 
divided  for  purposes  of  description 
into  three  parts;  viz.:  (1)  Subcla- 
vian, (2)  Axillary,  and  (3)  Brachial. 

The  subclavian  artery  passes  a 
short  way  up  the  thorax  into  the 
neck,  and  then  turns  downward  to 
rest  on  the  first  rib.  At  the  lower 
border  of  the  first  rib  it  ceases  to  be 
called  subclavian,  and  is  continued 
as  the  axillary.  It  gives  off  large 
branches  to  the  brain,  back,  chest, 
and  neck. 

The  axillary  artery  passes  through 
the  axilla,  lying  to  the  inner  side  of 
the  shoulder  joint  and  upper  part  of 
the  arm.  It  gives  off  branches  to 
chest,  shoulder,  and  arm. 

The  brachial  artery  (continuation 
of  the  axillary)  extends  from  the  ax- 
FiG.  122.  — Deep   Axterior   iHarv  space  to  just  below  the  bend 

View  of  the  Arteries  of  the  '  ..... 

Arm.  Forearm,  and  Hand.  of   the    elbow,  where    it    divides    intO 


1  The  vertebral  arteries  are  branches  given  off  from  the  subclavian.  They  as- 
cend on  either  side  of  the  vertebral  column,  pass  through  the  foramen  magnum, 
and  at  the  base  of  the  brain  unite  to  form  the  basilar  artery. 


Chap.  XI]  THE  VASCULAR  SYSTEM  193 

the  ulnar  and  radial  arteries.  It  may  be  readily  located,  b'ing 
in  the  depression  along  the  inner  border  of  the  biceps  muscle. 
Pressure  made  at  this  point  from  within  outward  against  the 
humerus  will  control  the  blood  supply  to  the  arm. 

The  ulnar,  the  larger  of  the  two  vessels  into  which  the  brachial 
divides,  extends  along  the  inner  side  of  the  forearm  into  the  palm 
of  the  hand,  where  it  terminates  in  the  superficial  palmar  arch. 

The  radial  artery  appears,  by  its  direction,  to  be  a  continuation 
of  the  brachial,  although  it  does  not  equal  the  ulnar  in  size.  It 
extends  along  the  outer  side  of  the  front  of  the  forearm  as  far  as 
the  lower  end  of  the  radius,  below  which  it  turns  around  the  outer 
border  of  the  wrist,  and  passes  forward  into  the  palm  of  the  hand. 
It  terminates  in  the  deep  palmar  arch.  The  superficial  and  deep 
palmar  arches  anastomose  and  supply  the  hand  with  blood. 

Thoracic  aorta.  —  The  branches  derived  from  it  are  numerous 
but  small.     The  principal  ones  are  :  — • 

(1)  The  intercostal  arteries  are  ten  or  eleven  on  each  side. 
They  arise  from  the  aorta  and  extend  outward  to  the  intercostal 
spaces.  They  give  off  branches  to  supply  the  muscles  of  the  back 
and  chest,  the  pleurae,  the  spinal  cord  and  its  membranes,  and  also 
the  vertebral  column.  Branches  from  the  third,  fourth,  fifth, 
and  sixth  supply  the  mammary  glands.     (See  page  453.) 

(2)  The  pericardial  arteries  pass  to  the  pericardium  and  supply 
it  with  blood. 

(3)  The  bronchial  arteries  are  three  in  number  and  pass  one 
to  the  right  and  two  to  the  left  lung.  Branches  from  these  arteries 
ramify  through  the  lung  tissue  and  supply  it  with  nutritive  material. 
Branches  are  also  distributed  to  the  bronchial  tubes,  oesophagus, 
and  pericardium. 

(4)  The  oesophageal  arteries  are  four  or  five  in  number  and 
supply  the  oesophagus. 

(5)  The  posterior  mediastinal  arteries  pass  backward  between 
the  lungs  to  the  thoracic  vertebra  and  supply  the  lymph  nodes 
found  in  the  mediastinum.     (See  page  242.) 

Abdominal  aorta.  —  It  gives  off  numerous  branches,  which  may 
be  divided  into  two  sets :  — 

1.  Visceral,  or  those  which  supply  the  viscera. 

2.  Parietal,  or  those  which  are  distributed  to  the  walls  of  the 
abdomen. 


194  ANATOMY   FOR  NURSES  [Chap.  XI 

Visceral  group :  — 

(a)  The  coeliac  axis  is  a  short,  wide  vessel,  usually  not  more  than 
half  an  inch  (12.5  mm.)  in  length,  which  arises  from  the  front  of  the 
aorta,  just  below  the  opening  in  the  diaphragm.  It  divides  into 
three  branches;  viz.  (1)  the  gastric,  which  supplies  the  stomach; 


Fig.  123.  —  Superior  Mesenteric  Artery.     (Gerrish.) 

(2)  the  hepatic,  which  supplies  the  liver  and  the  duodenum  or 
portion  of  the  intestine  nearest  to  the  stomach;  and  (3)  the 
splenic,  which  supplies  the  spleen,  and  .also  takes  part  in  the  blood 
supply  of  the  stomach  and  pancreas. 

(6)  The  superior  mesenteric  artery  arises  from  the  fore  part  of 
the  aorta,  a  little  below  the  coeliac  axis.     It  supplies  the  whole  of 


Chap.  XI] 


THE  VASCULAR  SYSTEM 


195 


the  small  intestine  beyond  the  first  portion,  and  half  of  the  large 
intestine. 

(c)  The  inferior  mesenteric  artery  arises  from  the  front  of  the 
aorta,  about  an  inch  and  a  half  (38  mm.)  above  its  bifurcation, 
and  supplies  the  lower  half  of  the  large  intestine.     Contiiuied 


INFERIOR 
^   MESENTERIC 


INFERIO 
HEMORRHOIDAL 


Fig.  124.  —  Inferior  iSlESENTERic  Artery.     (Gerrish.) 

under  the  name  of  the  superior  hemorrhoidal  artery,  it  also  takes 
part  in  the  blood  supply  of  the  rectum. 

(d)  The  renal  arteries  are  of  large  size,  in  proportion  to  the  bulk 
of  the  organs  (kidneys)  which  they  supply.  They  arise  from  the 
sides  of  the  aorta,  about  half  an  inch  (12.5  mm.)  below  the  superior 
mesenteric  artery,  that  of  the  right  side  being  generally  a  little 


196  ANATOMY  FOR  NURSES  [Chap.  XI 

lower  down  than  that  of  the  left.  Each  is  directed  outward,  so 
as  to  form  nearly  a  ri<;ht  angle  with  the  aorta. 

(e)  The  supra-renal  arteries  are  of  small  size.  They  arise  from 
the  side  of  the  aorta,  a  little  above  the  superior  mesenteric.  They 
supply  the  supra-renal  or  adrenal  bodies.     (See  page  316.) 

(/)  The  spermatic  arteries  in  the  male  arise  close  together  from 
the  front  of  the  aorta,  a  little  below  the  renal  arteries.  They 
are  distributed  to  the  testes, 

(g)  The  ovarian  arteries  in  the  female  arise  from  the  same  por- 
tion of  the  aorta  as  the  spermatic  arteries  in  the  male.  They 
supply  the  ovaries,  and,  joined  to  the  uterine  artery,  —  a  branch 
of  the  internal  iliac,  —  also  assist  in  supplying  the  uterus.  Dur- 
ing pregnancy  the  ovarian  arteries  become  considerably  enlarged. 

Parietal  group  :  — 

(a)  The  phrenic  arteries  arise  from  the  aorta  above  the  coeliac 
axis  and  are  distributed  to  the  diaphragm. 

(6)  The  lumbar  arteries  arise  from  the  aorta,  and  the  various 
branches,  dorsal,  spinal,  and  abdominal,  supply  the  muscles  and 
walls  of  the  respective  regions  that  their  names  suggest. 

(c)  The  middle  sacral  artery  arises  from  the  lower  end  of  the 
abdominal  aorta  and  passes  down  to  the  sacrum  and  coccyx. 

Common  iliac.  —  The  common  iliac  arteries,  commencing  at  the 
bifurcation  of  the  aorta,  pass  downward  and  outward  about  two 
inches  (50  mm.),  and  then  each  divides  into  the  internal  (or 
hypogastric)  and  the  external  iliac  arteries. 

The  internal  iliac  artery  (or  hypogastric)  supplies  branches 
to  the  pelvic  walls,  j)elvic  viscera,  the  external  genitals  and 
the  buttocks.  The  uterine  artery  in  the  female  which  supplies 
the  tissues  of  the  uterus  with  blood  is  a  very  important  branch 
of  the  internal  iliac. 

The  external  iliac  is  placed  within  the  abdomen,  and  extends 
from  the  bifurcation  of  the  common  iliac  to  the  lower  border  of 
the  inguinal  ligament,  where  it  enters  the  thigh  and  is  named 
femoral. 

The  external  iliac  artery  forms  a  large,  continuous  trunk,  which 
extends  downward  in  the  lower  limb,  and  is  named  in  successive 
parts  of  its  course  femoral,  popliteal,  and  posterior  tibial. 

The  femoral  artery  lies  in  the  upper  three-fourths  of  the  thigh, 
its  limits  being  marked  above  by  the  inguinal  (Poupart's)  liga- 


Chap.  XI]  THE   VASCULAR   SYSTEM 


197 


ment  and  below  by  the  opening  in  the  great  adductor  muscle, 
after  passing  through  which  the  artery  receives  the  name  of  pop- 


anterior  CRURAL 

NERVE 


EXTERNAL    _^_^ 
CiRCUIVIFLEX         (||[|lj 


SUPERIOR    EXTER 
ARTICULAR 


INFERIOR    EXTE 
ARTICULAR 


SUPERFICIAL    EPIGASTRIC 


SUPERFICIAL    EXTERNAL 
PUDIC 


DEEP    EXTERNAL 
PUOIC 


ASTOMOTICA 
MAGNA 


FERIOR    INTERNA! 
ARTICULAR 


Fig.  125.  —  Femoral  Artery.     (Gerrish.) 


liteal.     In  the  first  part  of  its  course  the  artery  lies  along  the 
middle  of  the  depression  on  the  inner  aspect  of  the  thigh,  known 


198 


ANATOMY   FOR   NURSES  [Chap.  XI 


INTERIOR    TIBIAL*!  p; 


RECURRENT  ~", 


ANTERIOR    TIBIAL 
NERVE 


ANTERIOR 
PERONEAL 


EXTERNAL 
MALLEOLAR 


INTERNAL 
MALLEOLAF 


OORSALIS 

PEDIS 


Fig.  120.  — Arteries  in  the  Dorsal 
Part  of  the  Leg.  (Gerrish.) 


Fig.  127.  —  A.vterior  Tibial  Artert. 
(Gerrish.) 


Chap.  XI]  THE  VASCULAR  SYSTEM  199 

as  Scarpa's  triangle.^  In  this  situation  the  beating  of  the  artery 
may  be  felt,  and  the  circulation  through  the  vessel  may  be  most 
easily  controlled  by  pressure. 

The  popUteal  artery,  continuous  with  the  femoral,  is  placed  at 
the  back  of  the  knee ;  just  below  the  knee-joint  it  divides  into 
the  posterior  tibial  and  anterior  tibial  arteries. 

The  posterior  tibial  artery  lies  along  the  back  of  the  leg,  and 
extends  from  the  bifurcation  of  the  popliteal  to  the  ankle,  where  it 
divides  into  the  internal  and  external  plantar  arteries. 

The  peroneal  artery  is  a  large  branch  given  off  by  the  posterior 
tibial  just  about  an  inch  (25  mm.)  below  the  bifurcation  of  the 
popliteal. 

The  anterior  tibial  artery,  the  smaller  of  the  two  divisions  of 
the  popliteal  trunk,  extends  along  the  front  of  the  leg  to  the  bend 
of  the  ankle,  whence  it  is  prolonged  into  the  foot  under  the  name  of 
the  dorsalis  pedis  artery.  This  unites  with  the  external  and 
internal  plantar  arteries  to  form  the  plantar  arch  which  supplies 
blood  to  the  foot.^ 

VEINS 

The  arteries  begin  as  large  trunks,  which  gradually  become 
smaller  and  smaller  until  they  end  in  the  small  capillary  tubes, 
while  the  veins  begin  as  small  branches  which  at  first  are  scarcely 
distinguishable  from  the  capillaries,  and  unite  to  form  larger  and 
larger  vessels.  They  differ  from  the  arteries  in  their  larger  capacity, 
greater  number,  thinner  walls,  and  in  the  presence  of  valves  which 
prevent  backward  circulation.  The  veins  may  be  divided  into 
two  sets  —  a  superficial  and  a  deep  set. 

The  superficial  set  —  are  found  immediately  beneath  the  skin. 

The  deep  set  —  accompany  the  arteries  and  are  usually  called 
by  the  same  names. 

Sometimes  two  deep  veins  accompany  an  artery,  and  are  then 
called  venae  comites,  or  companion  veins,  or  one  single  trunk  may 
accompany  an  artery,  and  then  be  known  as  the  vena  comes  of 
that  artery.     The  superficial  and  the  deep  veins  have  very  frequent 

1  Scarpa's  triangle  is  a  name  given  to  a  triangular  space  situated  on  the  upper, 
anterior,  and  inner  surface  of  the  thigh.  It  is  bounded  above  by  Poupart's  ligament, 
on  the  outer  side  by  the  sartorius  muscle,  and  on  the  inner  side  by  the  adductor. 

2  Drawing  t^ie  outline  of  the  aorta  with  its  branches  as  an  arterial  tree  will  greatly 
aid  the  student  in  mastering  the  arterial  distribution. 


200 


ANATOMY   FOR   NURSES  [Chap.  XI 


COMMUN'CATINO 


Fig.  128.  —  Arteries  of  the  Dorsum  of  the  Foot.     Of  the  dorsal  interosseous 
only  the  second  is  labelled.     (Gerrish.) 


Chap.  XIJ  THE   VASCULAR  SYSTEM  201 

communications  with  each  other,  and  the  anastomoses  of  veins 
are  always  more  numerous  than  those  of  arteries. 

The  systemic  veins.  —  The  systemic  veins  are  naturally  divided 
into  two  groups  :  — 

1.  Those  from  which  the  blood  is  carried  to  the  heart  by  the 
supsrior  vena  cava,  viz.  the  veins  of  the  head,  neck,  upper  extremi- 
ties, and  the  walls  of  the  thorax. 

2.  Those  from  which  the  blood  is  carried  to  the  heart  by  the 
inferior  vena  cava,  viz.  the  veins  of  the  lower  limbs,  the  lower 
part  of  the  trunk,  and  the  abdominal  viscera. 

Coronary  veins.  —  In  this  group  we  may  include  the  veins  of 
the  heart,  which,  however,  pass  directly  into  the  right  auricle 
without  entering  the  superior  vena  cava. 

Veins  of  the  head  and  neck.  —  The  blood  returning  from  the 
head  and  neck  flows  on  each  side  into  two  principal  veins,  the 
external  and  internal  jugular. 

External  jugular  veins.  —  The  right  and  left  external  jugular 
veins  are  formed  in  the  substance  of  the  parotid  glands  by  the 
union  of  two  of  the  veins  of  the  face.  This  union  takes  place  on  a 
level  with  the  angle  of  the  lower  jaw,  and  each  vein  descends  almost 
vertically  in  the  neck  to  its  termination  in  the  subclavian.  These 
two  veins  receive  the  blood  from  the  face  and  the  exterior  of  the 
cranium. 

Internal  jugular  veins.  —  These  veins  begin  at  the  base  of  the 
skull  and  descend  on  either  side  of  the  neck,  first"  with  the  external 
carotid,  then  with  the  common  carotid,  and  join  at  a  right  angle 
with  the  subclavian  to  form  the  innominate  (brachio-cephalic) 
vein.  They  receive  the  blood  from  the  veins  and  sinuses  of  the 
cranial  cavity.     (See  Fig.  131.) 

Sinuses.  —  The  blood  from  the  interior  of  the  skull  is  returned 
to  the  large  veins  by  venous  channels  that  are  called  sinuses. 
They  are  formed  by  a  separation  of  the  layers  of  the  dura  mater, 
the  fibrous  membrane  which  covers  the  brain.  Their  outer  wall 
consists  of  the  dura  mater,  and  their  inner  lining  of  endothelium  is 
continuous  with  the  lining  membrane  of  the  vessels  that  com- 
municate with  them.     (See  Fig.  184.) 

Veins  of  the  upper  extremities.  —  The  blood  from  the  upper 
limbs  is  returned  by  a  deep  and  a  superficial  set  of  veins.  The  deep 
veins  are  the  venae  comites  of  the  forearm  and  arm  and  are  called 


202 


ANATOMY   FOR  NURSES 


[Chap.  XI 


by  the  same  names.  They  communicate  with  the  superficial 
veins  at  the  hand  and  elbow,  and  the  vena  comes  of  the  brachial 
artery  unites  with  a  superficial  vein,  i.e.  the  basilic,  to  form  the 
axillary  vein. 

The  superficial  veins.  —  The  superficial  veins  are  much  larger 
than  the  deep,  and  take  a  greater  share  in  returning  the  blood, 


CEPHALIC  — 


MEDIAN 
CEPHALIC' 


MEDIAN    BASILIC 
ULNAR 

BRANCH    FROM 
DEEP    SET 


ANTERIOR 
ULNAR 


Fig.  129.  —  Superficial    Veins  of   Front  of   Forearm  and  Lower  Part  or 

Arm.     (Gerrish.) 

especially  from  the  distal  portion  of  the  limb.  They  commence 
in  two  plexuses,  one  on  the  back  of  the  hand  and  one  on  the  front 
of  the  wrist.     They  comprise  the  following :  — 

(1)  The  radial  vein  begins  in  the  dorsal  plexus  and  runs  up 
the  radial  side  of  the  forearm  to  a  little  above  the  bend  of  the 


Chap.  XI] 


THE   VASCULAR  SYSTEM 


203 


elbow,   where  it  joins   the  median   cephaHc  vein   to   form    the 
cephaHc. 

(2)  The  posterior  ulnar  begins  in  the  dorsal  plexus  and  extends 
upward  along  the  back  part  of  the  ulnar  side  of  the  forearm. 
Near  the  bend  of  the  elbow  it  usually  receives  the  anterior  ulnar 
vein. 

(3)  The  anterior  ulnar  vein  ascends  from  the  wrist  along  the 
ulnar  side  of  the  front  of  the  forearm. 


SUBCLAVIAN 
VEIN 


BASILIC   VEIN 

-^  PERFORATING 

DEEP  FASCIA 


.BASILI6   VEIN 


Fig.  130. — Superficial  Veins  of    Front  of  Arm    and    Shoulder.     (Gerrish.) 

(4)  The  common  ulnar  is  formed  by  the  union  of  the  anterior 
and  posterior  ulnar  veins  just  below  the  elbow,  and  after  a  short 
course  it  joins  the  median  basilic. 

(5)  The  median  vein  begins  in  the  plexus  on  the  wrist  and 
ascends  along  the  front  of  the  forearm  to  the  bend  of  the  elbow, 
where  it  bifurcates  into  the  median  basilic  and  median  cephalic 
veins. 

(6)  The  median  basilic  is  directed  upward  and  joins  the  common 
ulnar  to  form  the  basilic  vein.     The  median  basilic  is  the  vein 


204 


ANATOMY  FOR   NURSES 


[Chap.  XI 


usually  chosen  for  the  operation  of  phlebotomx'  or  intravenous  in- 
fusion. 

(7)  The  median  cephalic  yv'u\  is  directed  upward  and  joins  the 
radial  vein  to  form  the  ccplialic 

(8)  The  basilic  vein  ascends  in  the  groove  on  the  inner  side  of 
the  hiceps.  It  unites  with  the  inner  vena  comes  of  the  brachial 
arterv  to  form  the  axillarv  vein. 


INTERNAL 
MAMMARY 


Fig.  131.  —  Vei.vs  of  the  Neck  Atio  Upper  P.\rt  of  Thorax.     Front  View. 

(Gerrish.) 

(9)  The  cephalic  vein  ascends  in  the  groove  external  to  the 
biceps  and  ends  in  the  axillary  vein. 

The  axillary  vein.  —  The  axillary  vein  begins  at  the  junction  of 
the  inner  brachial  and  the  basilic,  and  ends  at  the  outer  border  of 
the  first   rib,   in   the    subclavian.     This   vein   accompanies   the 


Chap.  XI]  THE   VASCULAR  SYSTEM  205 

axillary  artery  and  collects  all  the  blood  of  the  upper  ex- 
tremities. 

The  subclavian  vein.  —  This  vein  continues  the  axillary  from 
the  first  rib  to  the  joint  between  the  sternum  and  clavicle,  where  it 
unites  with  the  internal  jugular  to  form  the  innominate  vein. 

The  innominate  veins.  —  The  innominate  (brachio-cephalic) 
veins,  commencing  on  each  side  by  the  union  of  the  subclavian 
and  internal  jugular,  transmit  the  blood  returning  from  the  head 
and  neck,  the  upper  limbs,  and  a  part  of  the  thoracic  wall ;  they 
end  below  by  uniting  to  form  the  superior  vena  cava.  Both  in- 
nominate veins  are  joined  by  many  side  tributaries  :  they  also 
receive,  at  the  junction  of  the  subclavian  and  internal  jugular,  the 
lymph ;  on  the  left  side  from  the  thoracic  duct,  and  on  the  right 
from  the  right  lymphatic  duct. 

The  superior  vena  cava.  —  The  superior,  or  descending,  vena 
cava,  is  formed  by  the  union  of  the  right  and  left  innominate 
veins,  just  behind  the  junction  of  the  first  right  costal  cartilage 
with  the  sternum.  It  is  about  three  inches  (75  mm.)  long,  and 
opens  into  the  right  auricle,  opposite  the  third  rib. 

Thoracic  veins.  —  The  great  majority  of  the  thoracic  veins 
follow  the  same  course  as  the  arteries,  and  bear  the  same  names. 
Two  exceptions  are  the  inferior  vena  cava  and  the  azygos  veins 
which  will  be  described  later. 

Veins  of  the  lower  extremities.  —  The  blood  from  the  lower 
limbs  is  also  returned  by  a  deep  and  a  superficial  set  of  veins. 
They  are  more  abundantly  supplied  with  valves  than  the  veins  of 
the  upper  limbs. 

The  deep  veins.  —  Below  the  knee  the  deep  veins  accompany 
the  arteries  in  pairs,  as  venae  comites,  and  as  in  the  upper  limbs  are 
called  by  the  same  names.  The  veins  from  the  foot  empty  into 
anterior  tibial  and  posterior  tibial  veins.  They  unite  to  form  the 
single  popliteal  vein,  which  is  continued  as  the  femoral  and  becomes 
the  external  iliac. 

The  superficial  veins.  —  The  internal  or  long  saphenous  and  the 
external  or  short  saphenous  are  the  two  largest  superficial  veins. 

The  internal  saphenous  extends  from  the  ankle  to  within  an 
inch  and  a  half  (38  mm.)  of  the  inguinal  ligament.  It  lies  along 
the  inner  side  of  the  leg  and  thigh  and  terminates  in  the  femoral 
vein. 


200 


ANATOMY  FOR  NURSES 


[Chap.  XI 


The  external  saphenous  arises  from  the  sole  of  the  foot,  and, 
passing  up  the  back  of  the  leg,  ends  in  the  deep  popliteal. 
The  femoral  veins.  —  These  vessels  are  a  continuation  of  the 


Fig.  132.  —  Superficial 
Veins  of  the  Front  of 
THE  Leg  and  Foot.  (Ger- 
rish.) 


Fig.  133.  —  Superficial  Veins 
OF  the  Front  of  the  Right 
Thigh.     (-Gerrish.) 


Chap.  XI] 


THE  VASCULAR  SYSTEM 


207 


k 


popliteal  veins  and  extend  from  the  opening  in  the  adductor 
magnus  to  the  level  of  the  inguinal  ligament. 

The  external  iliacs.  —  These  vessels  are 
a  continuation  of  the  femoral  veins,  and 
extend  from  the  level  of  the  inguinal  (Pou- 
part's)  ligament,  on  either  side. to  the  joint 
between  the  sacrum  and  the  ilium.  They 
receive  the  blood  from  the  deep  and  super- 
ficial veins  of  the  lower  limbs. 

The  internal  iliacs.  —  They  are  formed 
by  the  union  of  veins  corresponding  to  the 
branches  of  the  internal  iliac  arteries.  They 
accompany  the  internal  iliac  arteries  and 
unite  with  the  external  iliac  veins  to  form 
the  common  iliacs. 

The  common  iliacs.  —  The  common  iliacs 
extend  from  the  base  of  the  sacrum  to  the 
fourth  lumbar  vertebra,  and  then  the  two 
common  iliacs  unite  to  form  the  inferior 
vena  cava.  ^ 

The  inferior  vena  cava.  —  The  inferior,  or 
ascending,  vena  cava,  returns  the  blood  from 
the  lower  limbs,  pelvis,  and  abdomen.  It 
begins  at  the  junction  of  the  two  common 
iliacs,  and  thence  ascends  along  the  right 
side  of  the  aorta,  perforates  the  diaphragm, 
and  terminates  by  entering  the  right  auricle 
of  the  heart.  The  inferior  vena  cava  re- 
ceives many  tributaries,  the  chief  of  which 
are  the  lumbar,  ovarian,  renal,  and  hepatic 
veins. 

Supplementary  channel.  —  A  supplemen- 
tary channel  between  the  inferior  and  su- 
perior vena  cava  is  formed  by  the  azygos 
veins.  They  are  three  in  number  and  lie  on 
the  sides  of  the  front  of  the  vertebral  bodies. 

The  right  or  great  azygos  vein  is  an  upward  continuation  of  the 
lumbar  vein  which  communicates  with  the  common  iliac  vein, 
and  often  with  the  inferior  vena  cava  and  renal  vein.     It  ascends 


Fig.'  134.  —  Super- 
ficial Veins  of  the 
Dorsum  of  the  Leg. 
(Gerrish.) 


208 


ANATOMY   FOR  NURSES 


[Chap.  XI 


on  the  right  side  of  the  vertebral  column  to  the  level  of  the  fourth 
thoracic  vertebra,  where  it  empties  into  the  superior  vena  cava. 

The  left  lower  azygos  vein  commences  on  the  left  side  of  the  abdo- 
men ill  a  manner  similar  to  the  right.     It  ascends  on  the  left  side 


PER    END    OF 
ORACIC    DUCT 


Fig.  135.  —  Azygos  and  Intercostal  Veins.     (Gerrish.) 

of  the  vertebral  column,  and  at  about  the  level  of  the  eighth 
thoracic  vertebra  it  connects  with  the  right  azygos  vein. 

The  left  upper  azygos  vein  connects  above  with  the  superior 
intercostal  vein,  and  opens  below  into  either  the  left  lower  azygos, 


Chap.  XI] 


THE   VASCULAR  SYSTEM 


209 


Fig.  136.  —  Portal  System  of  Veins.  The  liver  is  turned  upward  and  back- 
ward, and  the  transverse  colon  and  most  of  the  small  intestines  are  removed. 
(Gerrish.) 


or  the  great  azygos  vein.  These  veins  receive  many  tributaries 
from  the  thoracic  walls  and  so  are  often  grouped  with  the  thoracic 
veins. 

It  is  important  to  remember  that  they  form  a  supplementary 


210 


ANATOINIY   FOR  NURSES 


[Chap.  XI 


channel  by  which  blood  can  be  conveyed  from  the  lower  part  of  the 
body  to  the  heart  in  case  of  obstruction  in  the  inferior  vena  cava. 

The  portal  system.  —  The  gastric,  splenic,  inferior  and  superior 
mesenteric  veins  which  bring  back  the  blood  from  the  intestinal 
tract  do  not  take  it  directly  to  the  inferior  vena  cava.  Just  back 
of  the  pancreas,  the  splenic  and  superior  mesenteric  unite  to  form 
the  portal  vein,  and  the  gastric  and  inferior  mesenteric  empty  into 
it.  The  portal  vein  runs  upward  and  to  the  right  for  about  three 
inches,  then  enters  the  liver,  where  it  divides  into  many  small  veins, 
and  these  finally  form  plexuses  of  capillaries.  These  capillaries 
unite  with  another  set  of  capillaries  which  arise  from  the  hepatic 
artery,  and  form  the  hepatic  vein,  which  carries  the  blood  from  the 
liver  to  the  inferior  vena  cava.  Thus  it  will  be  seen  that  the 
liver  receives  blood  from  two  sources  —  (1)  the  portal  vein  which 
carries  blood  to  the  liver  in  order  that  certain  chemical  changes 
may  take  place,  and  (2)  the  hepatic  artery  which  carries  blood  to 
the  liver  for  nutritive  purposes.  The  blood  from  both  sources  of 
supply  is  carried  from  the  liver  by  the  hepatic  vein. 

The  portal  vein  and  all  its  branches  constitute  the  portal  system, 
which  is  often  described  as  a  third  or  accessorv  svstem. 


Arteries     " 


SUMMARY 

'  Begin  as  large  trunks,  grow  smaller. 
Usually  deep  seated  for  protection. 

(Two  branches  of  nearlj'  equal  size. 
Trunk  gives  off  several  branches. 
One  branch  that  serves  as  an  axis. 
Anastomosis  or  inosculation  —  distal  ends  unite. 
Plexus  —  manj'^  inosculations  within  limited  area. 
Usually  straight  (facial  and  uterine  are  tortuous). 
Provides  for  pulmonary  circulation. 

Plight   pulmonary  artery 
1.  Pulmonary  arterj' 


Divisions 

of  the 

Vascular 

System 


Pulmonary 
System 


General 
System 


—  right  lung. 
Left  pulmonary  artery  — 
left  lung. 

2.  Capillaries. 

3.  Four  pulmonary  veins  —  two  from  each  lung. 
C  Pro\'ides  for  systemic  circulation. 

1.  Aorta  and  all  its  branches. 

2.  Capillaries. 

3.  Veins  empty  into  heart  either  directly  or  by 

means  of  inferior  and  superior  vena  cava. 


Chap.  XI] 


SUMMARY 


211 


Aorta 


Ascending 
Aorta 


Arch  of 
Aorta 


Right  and  left  coronary  —  supply  the  heart. 

Int.  carotid  —  brain 
Right  com- 
mon caro- 
tid 


Innominate 
1  to  2  in. 


Right    sub- 
clavian, 
—  axil- 
lary — 
brachial 


and  eye. 
Ext.  carotid — throat, 
tongue,  face,  ears, 
walls  of  cranium. 
C  Superficial 
Ulnar   <      palmar 
I      arch. 

Radial  P^^P     P^ 
[     mar  arch. 

Left  common  carotid  —  same  branches  as  right 

common  carotid. 
Left  subclavian  —  same  branches  as  right  sub- 
clavian. 

'  Intercostal  —  to  the  intercostal  spaces. 
II.  Pericardial  —  to  the  pericardium. 

Thoracic       Bronchial  —  to  the  lung  tissue. 

Aorta      I  (Esophageal  —  to  the  oesophagus. 
7  to  8  in.       Posterior  mediastinal  —  to  the  lymph  nodes  be- 
tween the  lungs. 
Diaphragm  muscle  is  dividing  line  between  thoracic  and  ab- 
'  dominal  aorta. 

Gastric  —  stomach. 
Hepatic  —  liver  and 

duodenum. 
Splenic    —    spleen, 
stomach,  and  pan- 
creas. 
Small    intestine    ex- 
cept duodenum. 
Half  of  large  inteS' 
tine. 
C  Lower  half  of  large 
<      intestine  and  rec- 
l      tum. 
Renal  —  kidneys. 
Supra-renal  —  supra-renal  bodies. 
Spermatic  —  testes. 
Ovarian  —  ovaries  and  uterus. 
'  Phrenic  —  diaphragm. 
Lumbar  —  dorsal,  spinal,  and  ab- 
dominal walls. 
Middle  sacral  —  sacrum  and  coccyx. 


III. 

Abdominal 

Aorta 

Sin. 


Visceral 
Group 


Coeliac  axis 


Sup. 
mesenteric 


Inf. 
mesenteric 


Parietal 
Group 


212 


ANATOMY  FOR   NURSES 


[Chap,  XI 


Common 

Iliac 
Arteries 
2  in. 


Internal  iliac  —  walls  and  viscera  of  pelvis. 


External 
iliac  — 
femoral 

—  popliteal 


Posterior 
tibial 

Anterior 
tibial 


r  Ext.  plantar  1  Plantar 
<  Int.  plantar  /  arch. 
I  Peroneal. 

Dorsalis  pedis. 


Veins 


Differ  from 
arteries 


■  Be^n  small,  grow  larger. 

'  Larger  capacity. 
Greater  number. 
{  Thinner  walls. 
Valves. 

,  More  frequent  anastomosis, 
r  Superficial. 
Sets  I  ^  j  Venae  comites 

\  Vena  comes  — 


Deep 


—  companion  veins, 
companion  vein. 


External 

Jugular 
Veins 


(Receive  blood  from  the   face  and   the  exterior  of  the 
cranium. 
Formed  in  parotid  gland,  terminate  in  the  subclavian. 

Internal  Tupu-  f  ^^^^ive  blood  from  the  veins  and  sinuses  of  the  cranial 

lar  Veins       L '^'^^'\  ,   ,    „ 

I  Begin  at  base  of  skull,  unite  with  subclavian. 

(1)  Receive  blood  from  the  deep  veins  of  the  forearm 
and  arm. 
They  accompany  the  arteries  and  are  called  by  the 
same  names. 

Radial. 

Posterior  ulnar. 
Anterior  ulnar. 
Common  ulnar. 
Median. 
Median  basilic. 
Median  cephaUc. 
Basilic. 
CephaUc. 

Formed  by  union  of  the  inner  brachial  and  basilic,  end 
in  the  subcla-vnan. 


Axillary  Veins  " 


(2)  Receive  blood  from   superficial 
veins 


Subclavian 
Veins 


Innominate 
Veins 


(  Continuation  of  axillary  from  first  rib  to  the  joint  be- 

l      tween  the  sternum  and  clavicle. 

I  Unite  with  internal  jugular  to  form  innominate. 

Transmit  blood  from  head,  neck,  upper  Umbs,  and  part 

of  thoracic  wall.     Receive  IjTnph. 
Formed  by  union  of  internal  jugular  and  subclavian. 
'•One  on  each  side  of  body. 


Chap.  XI] 


SUMMAEY 


213 


Superior  Vena 
Cava 

Thoracic  Veins 


Femoral 
Veins 


External 

Iliacs 
Internal 

Iliacs 
Common 

Iliacs 

Inferior  Vena 
Cava 


Supplemen- 
tary 
Channel 


Portal  Cir- 
culation 


Foi'ined  by  union  of  right  and  left  innominate  veins. 

Three  inches  long. 
Opens  into  right  auricle. 
—  Majority  foUow  same  course  and  bear  same  name  as 

arteries. 
Continuation  of  the  popliteal  and  extend  from  opening  in 

adductor  magnus  muscle  to  the  inguinal  ligament. 

(1)  Receive  blood  from  deep  veins  of  foot,  leg,  and  thigh. 
They  accompany  the  arteries  and  are  called  by  the 

same  names. 

(2)  Receive  blood  from  the  r  ^^^^^^^^^^  saphenous. 

superficial  vems,  two    ^^^^^^^  saphenous, 
are  important  I 

Continuation  of  femoral  veins.     Extend  from  inguinal 

hgament  to  the  joint  between  sacrum  and  ilium. 
Formed  by  union  of  veins  corresponding  to  branches  of 

internal  iliac  artery. 
Formed  by  union  of  external  and  internal  iUacs.    Extend 

from  base  of  sacrum  to  the  fourth  lumbar  vertebra. 
Formed  by  union  of  the  common  iliacs. 
Extends  from  fourth  lumbar  vertebra  to  the  right  auricle 

of  the  heart. 
Receives  many  tributaries  corresponding  to  arteries  given 

off  from  the  aorta. 

1.  Right  azygos  vein  ^  Connect  with  superior  vena 

2.  Left  lower  azygos  vein     i      cava  above,  and  inferior 

3.  Left  upper  azygos  vein    J      vena  cava  below. 
■  Splenic  vein  and  superior  \  Unite    to    form 

mesenteric  vein  /      portal  vein. 

Empty  into  the 
Gastric  vein  and  inferior 

mesenteric  vein 


Portal 
Vein 


portal  vein  be- 
fore it  enters 
the  liver. 
Carries  blood  to  liver,  breaks  up  into  capil- 
laries, then  unites  with  capillaries  from 
hepatic  artery  to  form  hepatic  vein. 
Hepatic  Vein  —  empties  into  inferior  vena  cava. 


CHAPTER   XII 

THE  VASCULAR  SYSTEM  CONTINUED:  THE  GENERAL  CIRCULA- 
TION; BLOOD  PRESSURE;  THE  PULSE;  LYMPH;  F(ETAL 
CIRCULATION 

THE    GENERAL  CIRCULATION  OF  THE  BLOOD 

To  trace  the  general  circulation,  we  will  begin  with  the  venous 
blood,  which  is  returned  to  the  right  auricle  by  the  superior  and 
inferior  venae  cavae.  It  enters  and  fills  the  right  auricle,  and 
beyond  into  the  right  ventricle,  then  the  auricle  contracts  and 
forces  the  blood  over  the  open  tricuspid  valve  into  the  ventricle, 
which  has  already  been  passively  filled,  and  now  becomes  well 
distended  by  the  extra  supply  of  blood.  Almost  instantly  the 
ventricle  contracts,  the  blood  gets  behind  the  cusps  of  the  tri- 
cuspid valve  and  closes  them,  and  thus  is  forced  over  the  open 
semilunar  valves  into  the  pulmonary  artery.  The  pulmonary 
artery  divides  into  two  branches  and  carries  the  blood  to  the  lungs, 
where  it  passes  through  the  innumerable  capillaries  that  surround 
the  alveoli  or  air  sacs  of  the  lungs.  These  capillaries  unite  to 
form  veins,  and  these  unite  to  form  larger  veins,  until  finally  two 
pulmonary  veins  return  the  blood  from  each  lung  to  the  left  auricle. 
The  left  auricle  now  contracts  and  forces  the  blood  over  the  open 
bicuspid  valve  into  the  left  ventricle,  just  as  described  for  the 
right  side  of  the  heart.  Upon  contraction  of  the  left  ventricle  the 
bicuspid  valve  is  closed  (in  the  same  way  as  the  tricuspid),  and 
the  blood  is  forced  over  the  open  semilunar  valve  into  the  aorta 
to  be  carried  through  the  body.  As  soon  as  the  ventricles  relax 
the  semilunar  valves  are  closed  by  the  excessive  pressure  within  the 
pulmonary  artery  and  the  aorta.  From  the  aorta  and  its  branches 
the  blood  travels  in  the  capillaries  to  every  part  of  the  body. 
The  capillaries  unite  to  form  veins,  and  finally  the  blood  is  returned 
by  means  of  the  vense  cavse  to  the  right  auricle,  which  brings  it 
back  to  where  we  started  from. 

The  puhnonary  circulation.  —  The  lesser  circulation  from  the 
right  ventricle  to  the  left  auricle  is  called  the  pulmonary  circula- 

214 


Chap.  XII]      GENERAL  CIRCULATION  OF  BLOOD      215 

tion.  The  purpose  of  the  pulmonary  circulation  is  to  carry  the 
blood  which  has  been  through  the  system,  giving  up  oxygen  and 
collecting  carbon  dioxide,  to  the  air  sacs  of  the  lungs,  where  the 


Pulmonary  artery. 


Superior  ca\a  or  vein 
from  head  and  necl<. 


Right  auricle. 
Inferior  vena  cava- 


Right  ventricle.  - 


Portal  circulation. 


Second  renal  circu- 
lation. 


Pulmonary  capillaries. 

Pulmonarj'  veins. 

Aorta. 

Arteries   to  head  and 
neck. 

Left  auricle. 
Left  ventricle. 


Gastric  and  intostinal 
vessels. 


;.7— ...First  renal  circulation. 


Systemic  capillaries. 


Fig.  137.  —  Diagram  of  the  Circulation.     (Halliburton.) 


red  corpuscles  are  recharged  with  oxygen,  and  the  carbon  dioxide 
is  feduced  to  a  standard  amount. 

The  systemic  circulation.  —  The  more  extensive  circulation, 
from  the  left  ventricle  to  all  parts  of  the  body,  and  the  return  to 
the  right  auricle,  is  known  as  the  systemic  circulation.  The  pur- 
pose of  the  systemic  circulation  is  to  carry  oxygen  and  nutritive 
substances  to  all  parts  of  the  body,  and  gather  up  waste  products. 

This  double  circulation,  pulmonary  and  systemic,  is  constantly 
and  simultaneously  going  on,  as  each  half  of  the  heart  is  in  a  literal 
sense  a  force  pump.  The  contraction  of  both  ventricles  drives  a 
certain  quantity  of  blood,  probably  amounting  to  six  ounces,  with 
great  force  into  both  the  aorta  and  pulmonary  artery. 

Factors  governing  circulation.  —  The  perfect  circulation  of  the 
blood  is  dependent  upon  certain  factors,  the  chief  of  which  are : 
(1)  the  heart-beat,  (2)  the  elasticity  and  extensibility  of  the  arterial 
walls,  (3)  the  position  and  direction  of  the  valves,  (4)  the  large 


216  ANATOMY  FOR  NURSES  [Chap.  XII 

numbtT  and  small  bore  of  the  capillaries,  and  (5)  the  large  size 
and  non-contractile  character  of  the  walls  of  the  veins. 

(1)  Heart-beat.  —  So  long  as  life  lasts,  the  muscular  tissue  of 
the  heart  contracts  and  relaxes  unceasingly  with  a  short  interval 
of  rest. 

The  contractions  of  the  heart  are  rhythmical ;  that  is  to  say, 
they  occur  in  a  certain  order.  First,  there  is  a  simultaneous  con- 
traction of  the  walls  of  both  auricles ;  immediately  following  this, 
a  simultaneous  contraction  of  both  ventricles ;  then  comes  a 
pause,  or  period  of  rest,  when  the  cycle  is  repeated. 

The  state  of  contraction  is  called  the  systole. 

The  state  of  dilation,  or  rest,  is  called  the  diastole.  During  the 
diastole,  or  period  of  rest,  the  blood  is  flowing  into  the  auricles  and 
beyond  into  the  ventricles  (the  auriculo-ventricular  valves  being 
open).  Then  the  auricles  and  ventricles  contract  again  in  the 
same  order  as  before,  and  their  contractions  are  followed  by 
the  same  pause  as  before. 

The  rhythmical  succession  of  the  systole  and  diastole  constitutes 
a  cardiac  cycle  and  corresponds  to  one  beat  or  pulsation  of  the 
heart.  Reckoning  on  the  number  of  heart-beats  as  72  per  minute, 
the  time  required  for  a  cardiac  cycle  will  be  about  0.8  of  a  second, 
and  half  of  this,  or  0.4  of  a  second,  represents  the  diastole  or  period 
of  rest. 

The  sounds  of  the  heart.  —  If  the  ear  be  applied  over  the  heart, 
certain  sounds  are  heard,  which  recur  with  great  regularity.  The 
first  sound  is  a  comparatively  long,  booming  sound ;  the  second, 
a  short,  sharp,  sudden  one.  The  sounds  resemble  the  syllables 
lubb-dup.  The  causes  which  produce  the  first  sound  are  sup- 
posed to  be  the  closure  of  the  auriculo-ventricular  valves,  the  con- 
traction of  the  ventricles,  and  the  cardiac  impulse  against  the 
chest  wall.  The  second  sound  is  caused  by  the  closure  of  the  semi- 
lunar valves.  The  first  sound  is  heard  best  at  the  apex ;  the 
second  sound  is  heard  best  at  the  base. 

In  certain  diseases  of  the  heart  these  sounds  become  changed 
and  obscure,  and  are  accompanied  by  various  distinctive  and 
characteristic  sounds  called  murmurs. 

Cause  of  the  heart-beat.  —  The  beat  of  the  heart  is  caused 
by  the  rhythmical  contractions  of  its  muscular  fibres.  These 
contractions  are  automatic,   and  do  not   depend  upon  the  cen- 


Chap.  XII]       GENERAL  CIRCULATION  OF  BLOOD       217 

tral  nervous  system.  That  the  contractions  of  the  heart  do 
not  depend  upon  the  nervous  system  is  certain,  for  the  heart 
will  continue  to  beat  for  some  time  after  its  removal  from  the 
body.  It  probably  depends  i?pon  a  power  inherent  in  the 
muscle  tissue,  and  this  power  is  most  highly  developed  in 
the  wall  of  the  right  auricle  between  the  openings  of  the  two 
venae  cavse.  Contractions  seem  to  start  in  this  area  and  pass 
first  over  the  walls  of  the  auricles,  and  thence  over  the  walls  of 
the  ventricles.  It  is  thought  that  the  contractions  are  stimulated 
by  the  chlorides  of  sodium,  potassium,  and  calcium  contained  in 
the  blood. 

Imiervation  of  the  heart.  —  As  previously  stated,  the  heart 
receives  inhibitory  nerve  fibres  from  the  pneumogastric  nerve, 
and  accelerator  fibres  from  the  sympathetic  system.  Both  the 
inhibitory  and  accelerator  fibres  are  in  a  state  of  constant,  though 
slight,  activity.  This  means  that  under  normal  conditions  the 
heart-beat  is  controlled  by  two  antagonistic  influences,  one  tending 
to  slow  the  heart  action,  and  the  other  to  quicken  it.  This  arrange- 
ment is  comparable  to  the  antagonistic  action  of  the  flexor  and 
extensor  muscles  and  probably  enables  the  heart  to  respond  more 
promptly  to  stimulation.  Stimulation  of  the  pneumogastric  may 
cause  marked  slowing  of  the  heart-beat,  and  depression  of  the 
pneumogastric,  or  stimulation  of  the  accelerator  fibres,  may  quicken 
the  heart-beat. 

(2)  The  elasticity  and  extensibility  of  the  arterial  walls.  —  Each 
time  the  ventricles  contract  they  force  about  six  ounces  of  blood 
into  arteries  that  are  already  full.  This  extra  blood  finds  room  for 
itself  partly  by  distending  the  arteries  and  partly  by  driving 
forward  the  blood  which  is  before  it.  The  arteries  are  capable  of 
distention  because  they  contain  a  large  amount  of  yellow  elastic 
tissue  in  their  coats.  Following  the  distention  the  arteries  recoil 
upon  the  contained  blood  and  cause  such  a  pressure  to  be  exerted, 
that  what  would  be  an  intermittent  stream  is  converted  into  a 
continuous  one.  They  thus  serve  not  only  as  conducting  tubes 
but  exert  a  force  that  assists  the  heart  in  driving  the  blood  into 
the  capillaries. 

The  elasticity  and  extensibility  of  the  arteries  change  with  the 
health  and  age  of  the  individual.  Sometimes  as  the  result  of 
disease,  and  always  as  we  grow  older,  the  arterial  walls  grow  stiffer 


218  ANATOMY   FOR   NURSES  [Chap.  XII 

and  more  rigid,  and  become  less  well  adapted  for  the  unceasing 
work  they  are  called  upon  to  perform.  This  condition  is  kncnvn 
as  arteriosclerosis. 

(3)  The  position  and  direction  of  the  valves.  —  The  position 
and  direction  of  the  tricuspid  and  bicuspid  valves  permit  the 
ventricles  to  fill  during  their  period  of  relaxation,  and  prevent  the 
backward  flow  when  they  are  emptying  themselves.  The  aortic 
and  pulmonary  valves  allow  blood  to  pass  out  during  each  con- 
traction of  the  ventricles,  but  not  to  return  from  either  artery  into 
the  heart  when  the  resting  stage  ensues.  The  valves  also  show 
signs  of  age  as  years  advance,  and  even  if  not  injured  by  disease, 
do  not  adjust  themselves  so  perfectly  as  in  early  life. 

(4)  The  large  number  and  small  bore  of  the  capillaries.  —  The 
total  number  of  capillaries  is  so  immense  tiiat,  e\en  though  each 
individual  one  is  small,  their  total  capacity  is  several  hundred 
times  greater  than  that  of  the  aorta.  This  is  due  to  the  fact  that 
each  time  an  artery  divides,  the  total  capacity  of  its  branches  is 
greater  than  that  of  the  parent  artery,  although  each  of  the  indi- 
vidual branches  is  of  smaller  calibre.  In  this  way  the  bed  of  the 
blood  stream  is  becoming  greater  until  we  reach  the  capillaries, 
and  then  it  is  increased  enormously.  The  eft'ect  of  this  arrange- 
ment is  to  make  the  blood  flow  rapidly  through  the  larger  arteries, 
more  slowly  in  the  smaller  and  more  numerous  arteries,  and 
slowest  of  all  in  the  capillaries. 

(5)  The  large  size  and  non-contractile  character  of  the  walls  of 
the  veins.  —  In  the  case  of  the  veins  the  conditions  we  have 
described  are  reversed.  The  size  and  capacity  of  a  vein  is  always 
less  than  the  size  and  capacity  of  its  tributaries,  hence  the  total 
bed  of  the  blood  stream  is  becoming  continually  smaller  but  never 
so  small  as  in  the  corresponding  arteries.  A  vein  is  always  twice 
the  size,  often  more  than  twice  the  size,  of  the  corresponding  artery. 
On  leaving  the  capillaries  the  blood  flows  faster  because  the  bed 
of  the  stream  becomes  narrower,  but  its  speed  in  a  vein  is  little 
more  than  half  that  in  a  corresponding  artery,  because  the  bed  is 
twice  as  great.  The  veins  contain  very  little  elastic  tissue  in 
their  walls,  hence  they  are  not  capable  of  distention  and  con- 
traction as  the  arteries  are.  As  the  blood  flows  in  a  steady  stream, 
and  the  diameter  of  the  veins  is  large,  the  non-contractile  character 
of  the  walls  offers  no  resistance  to  the  flow  of  blood  toward  the 


Chap.  XII]      GENERAL   CIRCULATION   OF  BLOOD      219 

heart.  The  valves  of  the  veins  also  render  assistance  in  this 
respect. 

Rate  of  blood  flow.  —  The  rate  at  which  the  blood  flows  is 
highest  in  the  arteries,  about  twelve  inches  to  a  second.  It  is 
lower  in  the  veins,  about  eight  inches  to  a  second.  In  the  capil- 
laries it  is  exceedingly  slow,  about  an  inch  to  a  minute.  When 
it  is  remembered  that  the  actual  service  of  the  blood  to  the  tissues 
is  rendered  in  the  capillaries  (since  the  walls  of  the  arteries  and 
veins  are  too  thick  to  permit  of  diffusion)  the  value  of  the  slow 
passage  is  obvious. 

Distribution  of  blood.  —  We  have  quoted  the  estimate  of  blood 
that  the  body  contains  as  four  quarts.  During  a  period  of  rest 
about  one-fourth  of  this  may  be  assumed  to  be  in  the  thorax,  one- 
fourth  in  the  skeletal  muscles,  one-fourth  in  the  liver,  and  the 
remaining  fourth  elsewhere.  Activity  of  any  part  of  the  body  will 
increase  the  supply  to  that  part,  and  lessen  the  supply  in  another 
part.  When  the  digestive  organs  are  active,  other  parts  of  the 
body  are  kept  short  of  blood,  but  any  condition  that  dilates  the 
vessels  of  the  skin  will  lessen  the  amount  of  blood  sent  to  the 

digestive  organs. 

BLOOD  PRESSURE 

By  blood  pressure  is  meant  the  pressure  the  blood  exerts  against 
the  walls  of  the  vessels  in  which  it  is  contained.  The  term  includes 
arterial,  capillary,  and  venous  pressure. 

Arterial  pressure.  —  When  an  artery  is  severed,  the  flow  of 
blood  from  the  proximal  end  (that  on  the  heart  side)  comes  in 
jets  corresponding  to  the  heart-beats,  provided  the  artery  be  near 
the  heart.  The  larger  the  artery,  and  the  nearer  to  the  heart, 
the  greater  the  force  with  which  the  blood  issues,  and  the  more 
marked  the  intermittence  of  the  flow.  This  indicates  that  the 
blood  in  the  arteries  is  under  a  high  pressure,  and  the  factors  which 
produce  and  maintain  this  pressure  are :  — 

1.  The  force  of  the  contraction  of  the  ventricles. 

2.  The  extra  supply  of  blood  which  the  heart  forces  into  arteries 
that  are  already  full. 

3.  The  semilunar  valves  which  prevent  regurgitation  of  the  blood 
into  the  ventricles,  when  the  ventricles  relax. 

4.  The  elasticity  of  the  arteries,  which  enables  them  to  dilate  to 
receive  the  extra  supply  of  blood,  then  to  contract. 


220  ANATOMY  FOR  NURSES     .r     (Cha^.  XII 

5.  The  resistance  oflFered  by  the  arterioles.  C-'^'V}  \l 

6.  The  increased  surface  over  which  the  blood  flows  in  the  capil- 
laries. 

When  the  blood  leaves  the  left  ventricle  the  high  pressure  which  it 
exerts  against  the  wall  of  the  aorta  may  be  regarded  as  a  measure 
of  energy.  This  energy  is  transformed  into  heat  in  overcoming 
the  friction  encountered  in  the  vessels.  When  the  blood  reaches 
the  arterioles,  the  surface  is  multiplied  and  the  friction  increased. 
This  offers  an  impediment  to  the  flow,  and  the  result  is  a  decided 
drop  in  the  pressure. 

Arterial  pressure  is  not  uniform,  but  varies  (1)  with  the  systole 
and  diastole  of  the  heart,  being  greater  during  the  systole ;  (2)  it 
is  less  in  youth,  and  increases  as  we  grow  older,  because  the  arteries 
are  less  elastic ;  (3)  conditions  of  health  may  affect  the  normal 
muscular  tone  of  the  arteries  and  heart.  When  the  arteries  lose 
their  tone,  or  the  heart-beat  loses  its  force,  the  blood  pressure  is 
low.  When  the  arteries  are  over-constricted,  or  the  heart  over- 
stimulated,  the  blood  pressure  is  high. 

Capillary  pressure.  —  The  pressure  of  blood  in  the  capillaries 
is  much  lower  than  in  the  arteries,  but  is  high  considering  the  thick- 
ness of  the  capillary  walls.  It  depends  upon  the  condition  of  the 
arterioles  :  if  they  dilate,  the  capillary  pressure  rises ;  if  they  con- 
strict, the  capillary  pressure  falls.  The  phenomena  produced  by 
these  local  variations  in  the  blood  supply  of  certain  parts  are  very 
familiar  to  us :  the  redness  of  the  skin  produced  by  an  irritating 
application,  the  blushing  or  paling  of  the  face  from  mental  emotion, 
the  increased  flow  of  blood  to  the  mucous  membranes  during 
digestion,  being  all  instances  of  this  kind. 

Venous  pressure.  —  When  a  vein  is  severed,  the  flow  of  blood, 
which  is  chiefly  from  the  distal  end  (that  away  from  the  heart), 
is  not  intermittent,  but  continuous ;  the  blood  comes  out  with 
comparatively  little  force,  and  "  wells  up  "  rather  than  "  spurts 
out."  This  indicates  that  the  blood  pressure  in  the  veins  is  low. 
It  is  influenced  by  :  — 

1 .  The  presence  of  valves  which  prevent  a  backward  flow. 

2.  Respiration.  The  effect  of  inspiration  is  to  suck  venous 
blood  into  the  thorax,  empty  the  large  veins,  and  cause  a  fall  in 
the  blood  pressure.  The  effect  of  expiration  is  to  offer  a  slight 
resistance  to  the  flow  of  blood  into  the  thorax  and  thus  raise  the 
blood  pressure  in  the  large  veins. 


Chap.  XII]      GENERAL   CIRCULATION   OF  BLOOD      221 

Method  of  determining  blood  pressure.  —  We  can  gain  some 
idea  of  the  blood  pressure  by  placing  the  fingers  over  a  large 
artery  where  the  pulsation  can  be  felt.  If  the  vessel  is  tense  and 
hard  to  compress,  it  indicates  high  blood  pressure.  If,  however, 
it  is  easy  to  obliterate  the  pulsation  by  pressure  of  the  fingers, 
the  blood  pressure  is  low.  Of  late  years  several  forms  of  apparatus 
have  been  devised  by  which  a  more  accurate  knowledge  can  be 
obtained.  This  apparatus  is  called  a  sphygmomanometer,  and  con- 
sists of  an  air  pump  which  is  connected  by  means  of  an  inverted 
T  (_L)  shaped  rubber  tubing  with  an  elastic  bag  covered  on  the 
outside  by  a  leather  cuff,  and  a  mercury  manometer. 

The  elastic  bag  covered  with  the  cuff  is  buckled  snugly  around 
the  arm  above  the  elbow.  The  bag  is  blown  up  by  means  of  the  air 
pump  and  exerts  pressure  upon  the  brachial  artery  until  no  pulsa- 
tion can  be  felt  in  the  radial  artery  at  the  wrist.  The  amount  of 
pressure  that  is  being  exerted  upon  the  arm  is  indicated  by  the 
mercury  manometer,  and  should  be  read  the  moment  the  pulse  dis- 
appears. This  will  give  the  maximum  or  systolic  pressure.  As  the 
pressure  on  the  arm  is  lowered,  the  pulse  reappears,  and  the  lowest 
position  of  the  mercury  gives  the  minimum  or  diastolic  pressure. 

Normal  degree  of  blood  pressure.  —  The  average  normal  degree 
of  blood  pressure  exerted  on  the  walls  of  the  brachial  artery  is 
about  110  to  116  mm.  systoHc;  and  65  to  75  mm.  diastoHc. 
Pressure  varies  with  age,  and  even  in  health  is  not  constantly 
the  same.  Increase  of  the  force  or  rate  of  the  heart-beat  in- 
creases the  pressure.  The  effect  of  cold,  also  of  certain  drugs, 
e.g.  adrenalin,  is  to  constrict  the  arteries  and  raise  the  blood  press- 
ure. On  the  other  hand  the  effect  of  heat,  and  of  some  drugs,  e.g. 
amyl  nitrite,  is  to  dilate  the  arteries  and  lower  the  blood  pressure. 

THE  PULSE 

When  the  finger  is  placed  on  an  artery,  a  sense  of  resistance 
is  felt,  and  this,  resistance  seems  to  be  increased  at  intervals, 
corresponding  to  the  heart-beat,  the  wall  of  the  artery  at  each 
heart-beat  being  felt  to  rise  up  or  expand  under  the  finger.  This 
alternate  contraction  and  expansion  of  the  artery  constitutes 
the  pulse ;  and  in  certain  arteries  which  lie  near  the  surface  this 
pulse  may  be  seen  with  the  eye.  Wlien  the  finger  is  placed  on 
a  vein,  very  little  resistance  is    felt;   and,  under  ordinary  cir- 


222  ANATOMY   FOR   NURSES  [Chap.  XII 

cumstances,  no  pulse  can  be  perceived  by  the  touch  or  by 
the  eye. 

As  each  expansion  of  an  artery  is  produced  by  a  contraction  of 
the  heart,  the  pulse,  as  felt  in  any  superficial  artery,  is  a  convenient 
guide  for  ascertaining  the  character  of  the  heart's  action. 

Locations  where  the  pulse  may  be  felt.  —  The  pulse  may  be 
counted  wherever  an  artery  approaches  the  surface  of  the  body. 
These  locations  are  :  — 

(1)  The  facial  artery,  where  it  passes  over  the  lower  jawbone. 

(2)  The  temporal  artery,  above  and  to  the  outer  side  of  the  outer 
canthus  of  the  eye. 

(3)  The  brachial  artery,  along  the  inner  side  of  the  biceps  muscle. 

(4)  The  radial  artery,  on  the  thumb  side  of  the  wrist.  On  ac- 
count of  its  accessible  situation  the  radial  artery  is  usually  em- 
ployed for  this  purpose. 

(5)  The  femoral  artery,  where  it  passes  over  the  pelvic  bone. 

(6)  The  dorsalis  pedis,  on  the  dorsum  of  the  foot. 

Points  to  note  in  feeling  a  pulse.  —  In  feeling  a  pulse  the  follow- 
ing points  should  be  noted. 

(1)  Frequency,  or  the  number  of  pulse-beats  per  minute. 

(2)  Strength,  or  the  force  of  the  heart-beat. 

(3)  Regularity,  or  the  same  number  of  beats  per  minute. 

(4)  Equality.  —  Each  beat  should  have  the  same  force,  not  some 
strong  and  some  weak.  It  sometimes  happens  that  a  beat  is  missed 
because  the  heart-beat  is  too  weak  to  distend  the  artery.  This  is 
called  an  intermittent  pulse. 

Occasionally  there  is  a  lack  of  tone  in  the  arterial  walls  and  a 
dicrotic  pulse  is  felt.  This  means  that  the  pulsations  are  divided 
and  the  second  part  of  the  beat  is  weaker  than  the  first. 

(5)  Tension  or  the  strength  of  the  blood  pressure.  This  is  in- 
dicated by  the  amount  of  force  that  is  required  to  obliterate  the 
pulse. 

Average  frequency  of  the  pulse.  —  The  average  frequency  of 
the  pulse  in  man  is  seventy-two  beats  per  minute.  This  rate  may 
be  increased  after  eating  or  by  muscular  action.  Even  the  varia- 
tion of  the  muscular  effort  entailed  between  the  standing,  sitting, 
and  recumbent  positions  will  make  a  difference  in  the  frequency 
of  the  pulse  of  from  eight  to  ten  beats  per  minute.  ^Mental  excite- 
ment may  also  produce  a  temporary  acceleration,  varying  in  degree 


Chap.  XII]      GENERAL  CIRCULATION   OF   BLOOD      223 

with  the  pecuHarities  of  the  individual.  Age  has  a  marked  influ- 
ence. At  birth  the  pulse  rate  is  about  130  per  minute ;  at  three 
years,  100  ;  in  adult  life,  72  ;  in  old  age,  65.  It  is  somewhat  more 
rapid  in  women  than  in  men  and  is  lowered  during  sleep.  Idiosyn- 
crasies are  frequently  met  with.  A  person  in  perfect  health  may 
have  a  much  higher  or  a  much  lower  rate  than  72.  The  relative 
frequency  of  the  pulse  and  respirations  is  about  four  heart -beats 
to  one  respiration. 

As  a  rule,  the  rapidity  of  the  heart's  action  is  in  inverse  ratio 
to  its  force.  An  infrequent  pulse,  within  physiological  limits, 
is  usually  a  strong  one,  and  a  frequent  pulse  comparatively 
feeble.  The  same  is  true  in  disturbance  of  the  heart's  action 
in  disease,  the  pulse  in  fever  or  debilitating  affections  becoming 
weaker  as  it  grows  more  rapid. 

LYMPH 

Formation  of  lymph.  —  The  lymph  is  derived  from  the  blood 
in  the  capillaries,  but  the  exact  process  is  still  an  open  question. 
It  is  considered  probable  that  it  is  partly  a  process  of  transudation 
which  depends  on  the  permeable  nature  of  the  walls  of  the  capil- 
laries, and  partly  the  result  of  a  secretory  process  on  the  part  of 
the  endothelial  cells  lining  the  capillaries.  The  transudation 
theory  is  supported  by  the  fact  that  the  blood  in  the  capillaries 
is  under  greater  pressure  than  in  the  arteries  or  veins.  The 
secretory  process  is  supported  by  the  chemical  differences  between 
the  blood  and  the  lymph. 

Factors  controlling  the  flow  of  lymph.  —  The  onward  progress 
of  the  lymph  from  the  tissues  to  the  veins  is  maintained  chiefly 
by  three  things. 

(1)  Differences  in  pressure.  —  The  lymph  in  the  tissue  spaces 
is  under  greater  pressure  than  the  lymph  in  the  lymph  capillaries, 
and  the  pressure  in  the  large  lymphatics  near  the  ducts  is  much  less 
than  in  the  smaller  vessels.  Consequently  we  may  consider  that 
the  lymphatics  form  a  system  of  vessels  leading  from  a  region 
of  higher  pressure,  viz.  the  lymph  spaces  of  the  tissues,  to  a 
region  of  lower  pressure,  viz.  the  interior  of  the  large  veins  of 
the  neck. 

(2)  Muscular  movements  and  valves.  —  The  muscular  move- 
ments of  the  body  compress  the  hinphatics  and  force  the  lymph 


224  ANATOMY   FOR   NURSES  [Chap.  XII 

on  in  the  proper  direction.  The  numerous  valves  prevent  a 
return  flow  in  the  wrong  direction. 

(3)  Respiration.  —  During  each  inspiration  the  pressure  on  the 
thoracic  (hict  is  less  than  on  the  lymphatics  outside  the  thorax, 
and  the  lymph  is  accordingly  "  sucked  "  into  the  duct.  During 
the  succeeding  expiration  the  pressure  on  the  thoracic  duct  is  in- 
creased, and  some  of  its  contents,  prevented  by  the  valve  from 
escaping  below,  are  pressed  out  into  the  innominate  veins. 

OEdema.  —  The  hTiiph  in  the  various  IjTnph  spaces  of  the  body 
varies  in  amount  from  time  to  time,  but  under  normal  circum- 
stances never  exceeds  certain  limits.  Under  abnormal  condi- 
tions, these  limits  may  be  exceeded,  and  the  result  is  known  as 
oedema,  or  dropsy.  Similar  excessive  accumulations  may  also 
occur  in  the  larger  lymph  spaces,  the  serous  cavities. 

Among  the  possible  causes  of  oedema  are  :  — 

(1)  An  obstruction  to  the  flow  of  lymph  from  the  Ijinph  spaces. 

(2)  An  excessive  transudation,  the  lymph  gathering  in  the 
hmph  spaces  faster  than  it  can  be  carried  away  by  a  normal 
flow. 

Oedema  is  almost  always  due  to  the  latter  cause,  viz.  excessive 
transudation. 

FCETAL  CIRCULATION 

Certain  structures  are  necessary  to  the  performance  of  fcetal 
circulation,  but  are  of  no  use  after  birth.     They  are  as  follows  :  — 

(1)  Foramen  ovale.  —  An  opening  between  the  two  auricles. 
It  furnishes  direct  communication  between  them. 

(2)  Ductus  arteriosus.  —  A  blood-vessel  connecting  the  aorta 
and  pulmonary  artery. 

(3)  Ductus  venosus.  —  A  blood-vessel  connecting  the  umbili- 
cal vein  and  the  inferior  vena  cava. 

(4)  The  placenta  and  umbilical  cord.  —  By  means  of  the  pla- 
centa the  chikl  is  nourished  and  obtains  oxygen.  The  cord  is  made 
up  of  two  arteries  and  one  large  vein  protected  by  "  Wharton's 
jelly."  The  vein  carries  the  oxj'genated  blood  from  the  placenta 
to  the  foetus.  The  arteries  carry  the  impure  blood  from  the 
foetus  to  the  placenta.  After  birth  these  structures  are  of 
no  further  use.  It  is  important  that  the  "  foramen  ovale  " 
should  close  as  soon  as  the  child  breathes,  else  if  the  arterial 
and  venous  blood  continue  to  mix,  a  "  blue  baby  "  will  be  seen. 


Chap.  XII]      GENERAL   CIRCULATION   OF  BLOOD      225 


^^^J^IS^^ 


OESCE 
CAVA 


ARTERIAL  BLOOD 

VENOUS.     BLOOD 

Fig.  138.  —  Diagram  of  Circulation  before  Birth.     Foetal  type.     (Cooke.) 

Course  of  the  blood.  —  The  oxygenated  blood  for  the  nutrition 
of  the  foetus  is  carried  from  the  placenta  along  the  umbilical 
cord  by  the  umbilical  vein.     Entering  the  foetus  the  blood  is 


226  ANATOMY   FOR  NURSES  [Chap.  XII 

conveyed  into  the  inferior  vena  cava  partly  through  the  Hver 
but  chiefly  through  the  "  ductus  venosus,"  which  connects  these 
two  vessels.  From  the  inferior  vena  cava  it  enters  the  right 
auricle,  passes  through  the  foramen  ovale  into  the  left  auricle, 
thence  into  the  left  ventricle,  and  out  through  the  aorta,  which 
distributes  it  principally  to  the  upper  extremities.  The  blood 
from  the  head  and  upper  extremities  returns  by  the  superior 
vena  cava  to  the  right  auricle,  then  passes  into  the  right  ventricle, 
and  out  through  the  pulmonary  artery  to  the  lungs.  As  the 
lungs  in  the  foetus  are  solid,  they  require  very  little  blood  (only 
for  nutrition),  and  the  greater  part  of  the  blood  passes  through 
the  ductus  arteriosus  into  the  descending  aorta,  where,  mixing 
with  the  blood  delivered  to  the  aorta  by  the  left  ventricle,  it 
descends  to  supply  the  lower  extremities  of  the  foetus.  The 
chief  portion  of  this  blood  is  carried  to  the  placenta  by  the 
two  umbilical  arteries,  but  a  small  amount  passes  back  into  the 
ascending  vena  cava  and  mixes  with  the  blood  from  the  placenta. 
From  this  description  of  the  foetal  circulation,  it  will  be  seen  :  — 

1 .  That  the  placenta  serves  the  double  purpose  of  a  respiratory 
and  nutritive  organ,  receiving  the  venous  blood  from  the  foetus, 
and  returning  it  again  charged  with  oxygen  and  additional  nutri- 
tive material. 

2.  That  the  liver  receives  pure  blood  directly  from  the  placenta  ; 
hence  the  large  size  of  this  organ  at  birth. 

3.  That  the  blood  from  the  placenta  passes  almost  directly 
into  the  arch  of  the  aorta,  and  is  distributed  by  its  branches  to 
the  head  and  upper  extremities ;  hence  the  large  size  and  perfect 
development  of  these  parts  at  birth. 

4.  That  the  blood  in  the  descending  aorta  is  chiefly  derived 
from  that  which  has  already  circulated  in  the  upper  extremities, 
and,  mixed  with  only  a  small  quantity  from  the  left  ventricle, 
is  distributed  to  the  lower  extremities ;  hence  the  small  size  and 
imperfect  development  of  these  parts  at  birth. 

Changes  in  the  vascular  system  at  birth.  —  From  the  foregoing 
description  it  is  obvious  that  at  birth  very  important  changes  must 
take  place :  — 

1.  The  blood  clots  in  the  umbilical  vein,  between  the  usual 
ligature  and  the  liver,  also  in  the  ductus  venosus.  The  blood  clot 
becomes  organized  and  these  two  vessels  become  obliterated. 


Chap.  XII]      GENERAL  CIRCULATION   OF   BLOOD      227 

2.  As  respiration  commences,  the  blood  traverses  the  pul- 
monary arteries,  and  then  returns  to  the  heart  by  the  pulmonary 
veins ;  this  raises  the  blood  pressure  in  the  left  auricle,  and  causes 
the  valve  over  the  foramen  ovale  to  close. 

3.  The  blood  in  the  ductus  arteriosus  clots,  the  clot  organizes, 
and  the  ductus  arteriosus  becomes  a  fibrous  cord. 

4.  The  blood  in  the  hypogastric  arteries  also  clots,  the  clots 
organize  and  these  vessels  become  obliterated. 


228 


ANATOMY  FOR  NURSES 


[Chap.  XII 


General 
Circulation 


Piilmonary 
Circulation 


SUMMARY 

Right  auricle  to  right  ventricle,  then  pulmonary 
arteries  to  lungs.  Capillary  systen\.  Re- 
turn by  pulmonary  veins  to  left  auricle. 

Purpose  —  To  increase  oxygen  and  decrease 
carbon  dioxide. 


Systemic 
Circulation 


Factors 

Governing 

Circulation 


Heart-beat  ' 


Elasticity  and  Exten- 
sibility of  Arterial 
Walls 


'  Left  auricle  to  left  ventricle,  then  by  means  of 

aorta  and  its  branches  to  all  parts  of  the  bodj'. 

Capillary  system.     Return  by  veins  which 

empty  into  superior  and  inferior  venae  cavse. 

Carry,    and  r  Oxj'gen. 

give    up    to  <  Nutritive     ma- 
Purpose        ^      tissues  I      tcrials. 

Take  from  tis-  f  Carbon  dioxide, 
sues  I  Waste  products. 

1.  The  heart-beat. 

2.  The  elasticity  and  e.xtensibiUty  of  the  arterial  walls. 

3.  The  position  and  direction  of  the  valves. 

4.  The  large  number  and  small  bore  of  the  capillaries. 

5.  The  large  size  and  non-contractile  character  of  the  walls 

of  the  veins. 

(Cardiac  cycle,  72  per 
minute. 
Occupies  0.8     of     a 
second. 
1.  Closure  of  auriculo- ventricu- 
lar valves. 
Heart  Lubb  {  2.  Contraction  of  ventricles. 

Sounds  3.  Cardiac  impulse  against  chest 

wall. 
Dup  1.  Closure  of  semilunar  valves. 

(  Power  inherent  in  heart  muscle. 
(  Sodium. 
Stimulated  by  chlorides  <  Potassium. 
I  Calcium. 
Pueumogastric     nerve  —  inhibi- 
tory. 
Sympathetic     nerve  —  accelera- 
tor. 
Enables  them  to  stretch  and  receive  extra  amount 

of  blood. 
Enables  them  to  recoil  and  convert  intermittent 

into  continuous  stream. 
Arteriosclerosis  =  loss  of  elasticity  and  extensi- 
biUtv. 


Cause 


Innervation  • 


Chap.  XII] 


SUMMARY 


229 


Position  and  Direc- 
tion of  Valves 


Large  Number  and 
Small  Bore  of  the 
Capillaries 


Large  Size  and  Non- 
contractile  Charac- 
ter of  the  Walls  of 
the  Veins 


Distribution  of  Blood  • 


Permit  blood  to  flow  from  auricles  into  ventricles, 
7iot  in  reverse  direction. 

Permit  blood  to  flow  from  ventricles  into  arteries, 
not  in  reverse  direction. 

Disease  and  advancing  years  may  impair  adjust- 
ment. 

Total  number  is  immense. 

Each  one  is  microscopic. 

Total  capacity  several  hundred  times  greater  than 

aorta. 
Rapidity  of  blood  stream  reduced  by  enormous 

increase  in  number  of  vessels,  and  in  surface. 

f  Begin  small  —  grow  larger. 
Decrease  in  number  of  vessels  and  in  total  capacity. 
Vein  twice  as  large  as  corresponding  artery. 
Not  capable  of  distention  and  recoil,  hence  offer 
no  resistance  to  current  of  blood. 

'  Estimated  amount  of  blood  in  body,  4  qts. 
Estimated  amount  of  blood  in  thorax,  1  qt. 
Estimated  amount  of  blood  in  skeletal  muscles, 

1  qt. 

Estimated  amount  of  blood  in  liver,  1  qt. 
Amount  in  any  organ  increased  when  there  is  need. 
Amount  in  any  organ  decreased  when  need  is  over. 


Blood 
Pressure 


'  Pressure  blood  exerts  against  walls  of  vessels. 

High  —  Hemorrhage       from       cut       artery  — 
"  spurts  "  out. 

■  1.  Contraction  of  ventricles. 

2.  Extra  blood  forced  into  full 
arteries. 

3.  Semilunar    valves    prevent 
regiu-gitation. 

Maintained  by  <!  4.  Elasticity     and     recoil     of 
arteries. 

5.  Resistance  offered  by  arte- 
rioles. 

6.  Increased  surface  in   capil- 
laries. 

f  1.  Higher  during  systole. 
I  2.  Lower  during  diastole. 
Not  uniform      {  3.  Increases  with  age. 

I  4.  Decreases   if   heart    or   ar- 
[  teries  lose  their  tone. 


Arterial 


230 


ANATOMY   FOR  NURSES 


[Chap.  XII 


Blood 
Pressure 


Capillary 


Venous 


Determined 
by 


Normal 


Use  of  sphygmomanometer 


Pulse 


Lymph 


Much  lower  than  in  arteries. 
High  considering  thinness  of  walls. 

(  constriction  i 
Dependent  on  <  or  >  of  arterioles. 

I  dilatation     J 

(  Low  —  Hemorrhage  from  cut  vein  "  wells  up." 

<  _   „  ,  ,       (  Presence  of  valves. 

Influenced  bv    n  t^      ■    .■ 
{  '     [  Ilospiration. 

Pressure  of  finger  against  large  artery. 

1.  Air  pump. 
,  Elastic    bag 
covered  with 
leather  cuff. 
.  Merciu-y   ma- 
nometer. 

f  SystoUc  or  maximum  —  110  to  116  mm. 
I  Diastolic  or  minimum  —  65  to  75  mm. 
Alternate  contraction  and  expansion  of  artery. 
'  Facial  artery. 
Temporal  artery. 
Brachial  artery. 
Radial  artery. 
Femoral  artery. 
DorsaUs  pedis. 
Frequency. 
Strength. 
Regularity. 
EquaUty. 
Tension. 
Infant,  130 
Three  years,  100 
Adult,  72 
Old  age,  65 
Eating. 

Aluscular  activity. 
Mental  excitement. 
Age. 
Sleep. 

Condition  of  health. 
Idiosyncrasies. 

/  Process  of  transudation. 
I  Process  of  secretion. 

Differences  in  pressure. 

Muscular  movements  and  valves. 
I  Respiration. 


Locations 
where  Pulse 
may  be 
counted 


Points  to  note  " 


Pulse  Rate 


Changes  in 
Pulse    Rate 
may  be  due 
to 


Formation 

Factors       con- 
trolling flow 


Higher  in  women 
than  in  men. 


Chap.  XII] 


SUMMARY 


231 


(Edema 


Foetal 
Circulation 


Accumulation  of  lymph  in  tissues. 

1.  Obstruction  to  flow  of  lymph  from 
tissue. 


May  be  caused 
by 


Changes  in 
Vascular  System  < 
at  Birth 


1. 


2. 


2.  Excessive  transudation. 

Direct  communication  between  right  and  left  auricle 
by  means  of  foramen  ovale. 

Direct  communication  between  imibilical  vein  and 
inferior  vena  cava.     Ductus  venosus. 

Direct  communication  between  pulmonary  artery 
and  aorta.     Ductus  arteriosus. 

Oxygen  and  nutritive  substances  obtained  from 
placenta. 

Umbilical  vein  and  ductus  venosus  become  obliter- 
ated. 

2.  Respiration  stimulates  pulmonary  circulation ;  this 

raises  the   blood  pressure  in   left   auricle,   and 
closes  foramen  ovale. 

3.  Ductus  arteriosus  becomes  a  fibrous  cord. 

4.  Hypogastric  arteries  become  obliterated. 


1. 


CHAPTER  XIII 

RESPIRATORY  SYSTEM:  NOSE;  LARYNX;  TRACHEA;  BRONCHI; 
LUNGS.  —  RESPIRATION ;  ABNORMAL  TYPES  OF  RESPIRATION. 
MODIFIED  RESPIRATORY  MOVEMENTS 

The  process  of  respiration  is  dependent  upon  the  proper  func- 
tioning of  certain  organs,  which  we  group  together  and  call  a  res- 
piratory system.  A  respiratory  system  consists  essentially  of  a 
moist  and  permeable  membrane,  with  blood-vessels  containing 

AIR 

THIN  MUCOSA    |-  |-  |  .  I  ^         \         ^  \        —  |_  |- 

CAPILLARV  BLOOD  VESSEL     QD00Q(SC?Xg)O  Q  QGg)0<50  Q0QO  ©gQ 

Fig.   139.  —  Diagram  of  the  Essentials  of  a  Respiratory  System. 

(Gerrish.) 

a  high  percentage  of  carbon  dioxide  on  one  side,  and  air  or  fluid 
containing  a  high  percentage  of  oxygen  on  the  other.  In  most 
aquatic  animals  the  respiratory  organs  are  external  in  the  form  of 
gills  ;  in  terrestrial,  or  air-breathing  animals,  the  respiratory  organs 
are  situated  internally  in  the  form  of  lungs,  and  are  placed  in  com- 
munication with  the  nose  and  mouth  by  means  of  the  bronchi, 
trachea,  and  larynx. 

NOSE 

The  nose  is  the  special  organ  of  the  sense  of  smell,  but  it  also 
serves  as  a  passageway  for  the  entrance  of  air  to  the  respiratory 
organs.  It  consists  of  two  parts,  —  the  external  feature,  the  nose, 
and  the  internal  cavities,  the  nasal  fossae. 

The  external  nose  is  composed  of  a  triangular  framework  of  bone 
and  cartilage,  covered  by  skin  and  lined  by  mucous  membrane. 
On  its  under  surface  are  two  oval-shaped  openings  —  the  nostrils, 
which  are  the  external  openings  of  the  nasal  fossse.  The  margins 
of  the  nostrils  are  provided  with  a  number  of  stiff  hairs,  which  ar- 

232 


Chap.  XIII] 


RESPIRATORY  SYSTEM 


233 


rest  the  passage  of  dust  and  other  foreign  substances  carried  in  with 
the  inspired  air. 

The  nasal  fossae  are  two  irregularly  wedge-shaped  cavities, 
separated  from  one  another  by  a  partition,  or  septum,  the  upper 
part  of  which  consists  of  the  perpendicular  plate  of  the  ethmoid, 


Fig.  140.  —  Sagittal  Section  of  the  Face  and  Neck,  showing  the  Fibst 
Portions  of  the  Respiratory  and  Alimentary  Tracts.     (Gerrish.) 

and  of  the  vomer,  and  the  lower  part  of  cartilage.  The  turbinated 
bones  and  turbinated  processes  of  the  ethmoid,  which  are  ex- 
ceedingly light  and  spongy,  project  into  the  nasal  cavities,  and 
divide  them  into  three  incomplete  passages  from  before  back- 
wards, —  the  superior,  middle,  and  inferior  meatus.  The  palate 
and  maxillae  separate  the  nasal  and  mouth  cavities,  and  the  crib- 
riform plate  of  the  ethmoid  forms  the  partition  between  the 
cranial  and  nasal  cavities. 


234  ANATOMY   FOR  NURSES  [Chap.  XIII 

These  cavities  ^  communicate  with  the  air  in  front  by  the  anterior 
nares,  or  nostrils,  while  behind  they  open  into  the  back  of  the 
pharynx  by  the  two  posterior  nares. 

The  pituitary  membrane  (sometimes  called  the  Schneiderian  ^ 
membrane)  is  the  mucous  lining  of  the  nose.  It  closely  covers 
the  nasal  passages,  and  is  thickest  and  most  vascular  over  the 
turbinated  bones. 

Advantages  of  nasal  breathing.  —  Under  normal  conditions 
breathing  should  take  place  through  the  nose  only  (1)  because  the 
arrangement  of  the  turbinated  bones  makes  the  upper  part  of  the 
nasal  passages  very  narrow ;  (2)  these  passages  are  thickly  lined, 
and  freely  supplied  with  blood-vessels,  so  that  they  can,  even  in  the 
very  coldest  weather,  moisten  and  warm  the  air  before  it  reaches 
the  lungs;  and  (3)  the  presence  of  hairs  at  the  entrance  to  the 
nostrils  serve  as  filters. 

Sinuses  which  communicate  with  the  nose.  —  Opening  into  the 
nasal  cavities  are  minute  channels  which  connect  with  (1)  the 
frontal  sinuses,  (2)  the  ethmoidal  sinuses,  (3)  the  maxillary 
sinuses  or  antrums  of  Highmore,  and  (4)  the  sphenoidal  sinuses. 
The  pituitary  membrane  is  prolonged  into  these  sinuses,  and  inflam- 
matory processes  in  the  nose  may  extend  into  these  cavities. 

Mouth  and  pharynx.  — As  the  mouth  and  pharynx  are  more 
closely  associated  with  the  process  of  digestion  rather  than  respira- 
tion, they  will  be  described  with  the  digestive  organs.  The 
mouth  serves  as  a  passageway  for  the  entrance  of  air,  and  the 
pharynx  transmits  the  air  from  the  nose  or  mouth  to  the  larynx. 

RESPIRATORY  SYSTEM 

Under  this  heading  we  group  the  organs  which  are  concerned  in 
the  process  of  respiration.     In  man  they  are  as  follows :  — 

1.  Larynx.  3.  Bronchi. 

2.  Trachea.  4.  Lungs. 

1  Eleven  bones  enter  into  the  formation  of  the  nasal  cavities  :  the  floor  is  formed 
by  the  palate  (2)  and  part  of  the  maxillse  bones  (2)  ;  the  roof  is  chiefly  formed  by 
the  perforated  plate  of  the  ethmoid  bono  (1),  the  sphenoid  (1),  and  by  the  (2)  small 
nasal  bones ;  in  the  outer  walls  we  find,  in  addition  to  processes  from  other  bones, 
the  two  scroll-like  turbinated  bones  (2).     The  vomer  (1)  forms  part  of  the  septum. 

*  It  was  formerly  supposed  that  the  mucus  secreted  by  the  mucous  membrane 
of  the  nose  came  from  the  brain.  Schneider  was  the  name  of  the  anatomist  who 
first  disproved  this. 


Chap.  XIII] 


RESPIRATORY  SYSTEM 


235 


THE  LARYNX 

The  larynx  is  situated  between  the  base  of  the  tongue  and 
the  top  of  the  trachea,  in  the  upper  and  front  part  of  the  neck. 
Above  and  behind  lies  the  pharynx,  which  opens  into  the  oesoph- 
agus, or  gullet,  and  on  either  side  of  it  lie  the  great  vessels  of 
the  neck.     In  form,  the  larynx  is  narrow  and  rounded  below, 


Fig.  141.  — Larynx.     Viewed  from  above.      (Gerrish.) 

where  it  blends  with  the  trachea,  but  broad  above  and  shaped 
somewhat  like  a  triangular  box,  with  flat  sides  and  prominent 
ridge  in  front.  It  is  made  up  of  nine  pieces  of  fibro-cartilage, 
united  together  by  elastic  ligaments,  and  moved  by  numerous 
muscles. 

The  three  principal  cartilages  are  the  cricoid,  thyroid,  and 
epiglottis.  The  cricoid  resembles  a  seal  ring  with  the  hoop  part  in 
front  and  the  signet  part  in  the  back.  The  thyroid  resembles 
a  shield  and  is  the  largest.  It  rests  upon  the  cricoid  and  con- 
sists of  two  square  plates,  or  alse  (right  and  left),  which  are  joined 
together  in  front  and  form  by  their  union  the  laryngeal  promi- 
nence, called  Adam's  apple.  The  upper  portion  of  the  hind 
border  of  the  thyroid  is  called  the  superior  horn,  and  the  lower 
portion  the  inferior  horn  (see  Fig.  143).  The  epiglottis  is 
shaped  like  a  leaf.  The  stem  is  inserted  in  the  notch  between 
the  two  plates  of  the  thyroid.     The  larynx  is  lined  throughout 


236 


ANATOMY  FOR  NURSES 


[Chap.  XIIl 


by  mucous  membrane,  which  is  continuous  above  with  that  lining 
the  pharynx,  and  below  with  that  lining  the  trachea. 

The  glottis.  —  Across  the  middle  of  the  larynx  is  a  transverse 
partition,  formed  by  two  folds  of  the  lining  mucous  membrane, 
stretching  from  side  to  side,  but  not  quite  meeting  in  the  middle 
line.  They  thus  leave  in  the  middle  line  a  chink,  or  slit,  running 
from  front  to  back,  called  the  glottis.  The  glottis  is  protected 
by  the  leaf-shaped  lid  of  fibro-cartilage,  called  the  epiglottis,  which 

shuts  down  upon  the 
opening  during  the 
passage  of  food  or 
other  matters  into  the 
oesophagus. 

The  vocal  cords.  — 
Embedded  in  the  mu- 
cous membranes  at  the 
edges  of  the  slit  are 
fibrous  and  elastic  lig- 
a  m  e  n  t  s  ,  w  li  i  c  h 
strengthen  the  edges 
of  the  glottis  and  give 
them  elasticity.  These 
ligamentous  bands, 
covered  with  mucous 
membrane,  are  firmly 
attached  at  either  end 
to  the  cartilages  of  the 
larynx,  and  are  called 
the  true  vocal  cords, 
because  they  function 
in  the  production  of  the 
voice.  Al)ove  the  true 
vocal  cords  are  two 
false  vocal  cords,  so  called  because  they  do  not  function  in  the 
production  of  the  voice. 

Variations  in  size  of  glottis.  —  The  glottis  varies  in  shape  and 
size,  according  to  the  action  of  the  muscles  upon  the  laryngeal 
walls.  When  the  larynx  is  at  rest  during  quiet  breathing,  the 
glottis  is  V-shaped ;   during  a  deep  inspiration  it  becomes  almost 


Fig.  142.  —  Tuk   Larynx  as  seen  by   Means 

OF  THE    LaKYNUOSCOPE   IN   DIFFERENT  CONDITIONS 

OF  THE  Glottis.  A,  while  singing  a  high  note  ;  B, 
in  fiuiot  breathing ;  C,  during  a  deep  inspiration. 
I,  ba.se  of  tongue  ;  e,  upper  free  edge  of  epiglottis ; 
e',  cushion  of  the  epiglottis ;  ph,  part  of  anterior 
wall  of  pharynx ;  cv,  the  true  vocal  folds ;  cvs,  the 
false  vocal  folds ;    ir,  the  trachea  with  its  rings. 


Chap.  XIII] 


RESPIRATORY   SYSTEM 


237 


round,  while  during  the  production  of  a  high  note  the  edges  of 
the  folds  approximate  so  closely  as  to  leave  scarcely  any  open- 
ing at  all. 


fiiiperior 
Horn 


Inferior 
Horn 


Fig.  143.  —  Front  View  of  Cartilages  of  Larynx.     Trachea  and  Bronchi. 


Voice.  —  The  vocal  cords  produce  the  voice.  A  blast  of  air, 
driven  by  an  expiratory  movement  out  of  the  lungs,  throws  the 
two  elastic  cords  into  vibrations.  These  impart  their  vibrations 
to  the  column  of  air  above  them,  and  so  give  rise  to  the  sound 


238  ANATOMY   FOR  NURSES  [Chap.  XIII 

which  we  call  the  voice.  The  pharynx,  mouth,  and  nasal  cavities 
above  the  glottis  act  as  resonating  cavities,  and  by  alterations  in 
their  shape  and  size,  they  are  ai)le  to  pick  out  and  emphasize  cer- 
tain j)arts  of  the  tones  produced  in  the  larynx. 

Differences  between  male  and  female  voice.  —  At  puberty  in 
the  male,  the  larynx  enlarges,  giving  rise  to  what  is  commonly 
called  Adam's  apple.  The  increase  in  the  size  of  the  larynx  causes 
an  increase  in  the  length  of  the  vocal  cords.  To  this  is  due  the 
lower  pitch  of  the  voice  in  the  male. 

THE   TRACHEA 

The  trachea,  or  windpipe,  is  a  fibrous  and  muscular  tube. 
It  measures  about  four  and  a  half  inches  (112  mm.)  in  length, 
and  three-quarters  of  an  inch  (19  mm.)  from  side  to  side.  It 
extends  down  into  the  tliorax  from  the  lower  part  of  the  larynx 
to  opposite  the  third  thoracic  vertebra,  where  it  divides  into 
two  tubes,  —  the  two  bronchi,  —  one  for  eacli  lung. 

The  walls  are  strengthened  and  rendered  more  rigid  by  hoops 
of  cartilage  embedded  in  the  fibrous  tissue.  These  hoops  are 
C-shaped  and  incomplete  behind,  the  cartilaginous  rings  being 
completed  by  bands  of  plain  muscular  tissue  where  the  trachea 
comes  in  contact  with  the  oesophagus.  Like  the  larynx,  it  is 
lined  by  mucous  membrane,  and  has  a  ciliated  epithelium  upon 
its  inner  surface.  The  mucous  membrane,  which  also  extends 
into  the  bronchial  tubes,  keeps  the  internal  surface  of  the  air- 
passages  free  from  impurities ;  the  sticky  mucus  entangles  par- 
ticles of  dust  and  other  matters  breathed  in  with  the  air,  and  the 
incessant  movements  of  the  cilia  continually  sweep  this  dirt- 
laden  mucus  upward  and  outward. 

THE  BRONCHI 

The  two  bronchi,  into  which  the  trachea  divides,  differ  slightly; 
the  right  bronchus  is  shorter,  wider,  and  more  nearly  horizontal, 
the  left  bronchus  is  longer,  narrower,  and  more  nearly  vertical. 
They  enter  the  right  and  left  lung,  respectively,  and  then  break  up 
into  a  great  number  of  smaller  branches  which  are  called  the  bron- 
chial tubes,  or  bronchioles.  The  two  bronchi  resemble  the  trachea 
in  structure ;    but  as  the  bronchial  tubes  divide  and  subdivide 


Chap.  XIII] 


RESPIRATORY  SYSTEM 


239 


their  walls  become  thinner,  the  small  plates  of  cartilage  cease, 
the  fibrous  tissue  disappears,  and  the  finer  tubes  are  composed 
of  only  a  thin  layer  of  muscular  and  elastic  tissue  lined  by  mucous 
membrane. 

LUNGS 

The  lungs  are  cone-shaped  organs  which  occupy  almost  all  of  the 
cavity  of  the  thorax  that  is  not  taken  up  by  the  heart,  the  large 
blood-vessels,  the  lymphatics,  and  the  oesophagus.     Each  lung 


RIGHT   LUNG 


LEFT  LUNG 


Fig.  144.  —  Bronchi  and  Bronchioles.     The  lungs  have  been  widely  sepa- 
rated and  tissue  cut  away  to  expose  the  air-tubes.      (Gerrish.) 

presents  an  outer  surface  which  is  convex,  a  base  which  is  concave 
to  fit  over  the  convex  portion  of  the  diaphragm,  and  a  summit  or 
apex  which  rises  half  an  inch  above  the  clavicle.  On  the  inner 
surface  is  a  vertical  notch  called  the  hilum,  which  gives  passage 
to  the  bronchi,  blood-vessels,  lymph-vessels,  and  nerves. 

The  right  lung  is  the  larger  and  heavier ;  it  is  broader  than  the 
left,  owing  to  the  inclination  of  the  heart  to  the  left  side ;  it  is 
also  shorter  by  one  inch,  in  consequence  of  the  diaphragm  rising 


240  ANATOMY   FOR   NURSES  [Chap.  XIII 

higher  on  the  right  side  to  accommodate  the  liver.  The  right 
lung  is  divided  by  fissures  into  three  lobes,  upper,  middle,  and 
lower. 

The  left  lung  is  smaller,  narrower,  and  longer  than  the  right. 
It  is  only  divided  into  two  lobes,  upper  and  lower.     The  front 
border  is  deeply  notched  to  accommodate  the  heart. 

Anatomy  of  the  lungs.  —  The  lungs  are  hollow,  rather  spongy 
organs,  and  consist  of  the  bronchial  tubes  and  their  terminal 
dilatations,  numerous  blood-vessels,  lymphatics,  nerves,  and  an 
abundance  of  fine,  elastic  connective  tissue,  binding  all  together. 
(See  Fig.  99.)  Each  lobe  of  the  lung  is  composed  of  many 
lobules,  and  into  each  lobule  a  bronchiole  enters  and  terminates 
in  an  enlargement  having  more  or  less  the  shape  of  a  funnel, 
and  called  an  infundibulum.  From  each  infundibulum  there  is 
a  series  of  small  sac-like  j)rojections  known  as  alveoli,  the  walls 
of  which  are  honeycombed  with  cavities  called  the  air-cells.  In 
this  way  the  amount  of  surface  exposed  to  the  air  and  covered 
by  the  capillaries  is  immensely  increased. 

Blood-vessels  of  the  lungs.  —  Two  sets  of  vessels  are  distrib- 
uted to  the  lungs:  (1)  the  branches  of  the  pulmonary  artery, 
and  (2)  the  branches  of  the  bronchial  arteries. 

(1)  The  branches  of  the  pulmonary  artery  accompany  the 
bronchial  tubes  and  form  a  plexus  of  capillaries  around  the  al- 
veoli. The  walls  of  the  bronchioles  consist  of  a  single  layer  of 
flattened  epithelioid  cells,  surrounded  by  a  fine,  elastic  connec- 
tive tissue,  and  are  exceedingly  thin  and  delicate.  Immediately 
beneath  the  layer  of  flat  cells,  and  lodged  in  the  elastic  connective 
tissue,  is  this  very  close  plexus  of  capillary  blood-vessels  ;  and  the 
air  reaching  the  alveoli  by  the  bronchial  tubes  is  separated  from 
the  blood  in  the  capillaries  by  only  the  thin  membranes  forming 
their  respective  walls.  The  pulmonary  veins  begin  at  the  margin 
of  the  alveoli  and  return  the  blood  distributed  by  the  pulmonary 
artery. 

(2)  The  branches  of  the  bronchial  arteries  supply  blood  to 
the  lung  substance,  —  the  bronchial  tubes,  coats  of  the  blood- 
vessels, the  hmph  nodes,  and  the  pleura.  The  bronchial  veins 
return  the  blood  distributed  by  the  bronchial  arteries. 

Nerves.  —  The  substance  of  the  lungs  is  supplied  with  nerves 
which  are  derived  from  the  s.Mnpathetic  system,  and  from  branches 


,-n//^;  t  —Diagram  of  a  Lobule  of  the  Lung.  A  bronchiole  is  seen  divid- 
ing nto  two  branches,  one  of  which  runs  upward  and  ends  in  the  lobule.  la 
IVvpoh"  'l'\  ^'""^u  °^  i^f^'^dibula.  At  the  left  are  two  infundibula.  the 
aiveoh  of  which  presen    their  outer  surfaces.     Next  are  three  infundibula  in  ver- 

next  Jrourihe  fir  7'"  '  "if^'f  °Pf  ^"^  '''*°  *^"  "°°^™°^  passageway.  In  the 
nnpn,-n  f  I  ^  "^^"ndibulum  shows  a  pulmonary  arteriole  surrounding  the 
cC  n.     I  f  ^'^°/".«-  and  the  second  gives  the  same  with  the  addition  of  the 

close  capillary  network  in  the  wall  of  each  alveolus.  Around  the  fourth  group  is  a 
deep  deposit  of  pigment,  such  as  occurs  in  old  age,  and  in  the  lungs  of  those  who 

"rtet  n.h  et'f  —  *'l/''t  °!!  *^^  '^'•'^'^'^^^^'^  ^-^  -  ^--h  of  "the  pulmonar^ 
artery  (blue),  bringing  blood  to  the  infundibula  for  aeration.  Beginning  between 
the  infundibula  are  the  radicles  of  the  pulmonary  vein  (red),  a  root  of  which  ^ea 

nutrient  blood  to  the  bronchiole.     (Gerrish.) 
R  241 


242  ANATOMY  FOR  NURSES  [Chap.  XIII 

of  the  pneumogastric.  These  nerves  follow  the  course  of  the 
blood-vessels  and  bronchioles. 

Pleura.  —  Each  lung  is  enclosed  in  a  serous  sac,  the  pleura, 
one  layer  of  which  is  closely  adherent  to  the  walls  of  the  chest 
and  dia])hragni  (parietal) ;  the  other  closely  covers  the  lung 
(visceral).  The  two  layers  of  the  pleural  sacs,  moistened  by 
serum,  are  normally  in  close  contact ;  they  move  easily  upon 
one  another,  and  prevent  the  friction  that  would  otherwise  occur 
between  the  lungs  and  the  walls  of  the  chest  with  every  respiration. 
Inflammation  of  the  pleura  is  called  pleurisy. 

Mediastinum.  —  The  mediastinum  is  the  space  between  the  two 
pleural  sacs.  It  extends  from  the  sternum  to  the  spinal  column 
and  holds  a  portion  of  many  organs,  i.e.  the  trachea,  oesophagus, 
great  vessels  connected  with  the  heart,  ner^'es,  and  the  thoracic 
duct. 

RESPIRATION 

Function.  — The  main  purpose  of  respiration  is  to  supply  the  body 
with  oxygen  and  get  rid  of  the  excess  carbon  dioxide  which  results 
from  oxidation.  It  also  helps  to  equalize  the  temperature  of  the 
body  and  get  rid  of  excess  of  water.  To  accomplish  these  purjioses 
two  processes  are  necessary,  i.e.  external  and  internal  respiration. 

External  respiration.  —  This  takes  place  in  the  lungs  and  con- 
sists of  the  absorption  of  oxygen  from  the  air  in  the  alveoli,  and  the 
elimination  of  some  of  the  carbon  dioxide  and  water  from  the 
blood  in  the  capillaries.  External  respiration  consists  of  inspira- 
tion, or  the  process  of  taking  air  into  the  lungs,  and  expiration,  or 
the  process  of  expelling  air  from  the  lungs. 

Internal  respiration.  —  This  takes  place  in  the  cells  and  consists 
of  the  diffusion  of  oxygen  from  the  blood  in  the  capillaries  into  the 
tissues,  and  its  union  there  with  the  protoplasm  of  the  cells.  As 
a  result  of  this  union  or  oxidation  complex  bodies  are  broken 
up  into  simpler  ones,  such  as  carbon  dioxide  and  water,  and 
there  is  thus  liberated  a  great  deal  of  energy,  which  is  mani- 
fested in  the  increasing  of  muscular  activity  and  in  the  pro- 
duction of  heat.  The  carbon  dioxide  passes  by  diffusion  into 
the  venous  blood,  and  is  carried  by  it  to  the  right  side  of  the 
heart  and  thence  to  the  lungs,  a  certain  quantity,  however, 
escaping  from  the  blood  through  the  kidneys  and  skin. 


Chap.  XIII]  RESPIRATORY  SYSTEM  243 

Mechanism  of  inspiration  and  expiration.  —  During  inspiration 
the  cavity  of  the  chest  is  enlarged  in  all  three  diameters : 
(1)  antero-postepior,  (2)  lateral,  and  (3)  vertical.  This  is  brought 
about  by  the  action  of  the  intercostal  and  other  muscles,  which 
elevate  the  ribs  and  thereby  increase  the  antero-posterior  and 
lateral  diameters.  The  descent  of  the  diaphragm  increases  the 
vertical  diameter.  The  lungs  are  correspondingly  distended  to 
fill  the  enlarged  cavity.  To  prevent  a  vacuum  in  the  lungs,  air 
rushes  in  by  way  of  the  trachea  to  the  bronchi.  Upon  the  relaxa- 
tion of  the  inspiratory  muscles,  the  elasticity  of  the  lungs  and  the 
weight  and  elasticity  of  the  chest  walls  cause  the  chest  to  return 
to  its  original  size,  in  consequence  of  which  the  air  is  expelled  from 
the  lungs.  As  in  the  heart,  the  auricular  systole,  the  ventricular 
systole,  and  then  a  pause  follow  in  regular  order,  so  in  the  lungs  the 
inspiration,  the  expiration,  and  then  a  pause  succeed  one  another. 

Control  of  respiration.  —  Respiration  is  both  a  voluntary  and 
an  involuntary  act.  It  is  possible  for  a  short  time  to  increase  or 
retard  the  rate  of  respiration  within  certain  limits  by  voluntary 
effort,  but  this  cannot  be  done  continuously.  If  we  intentionally 
arrest  the  breathing  or  diminish  its  frequency,  after  a  short  time 
the  nervous  impulse  becomes  too  strong  to  be  controlled,  and  the 
movements  will  recommence,  as  usual.  If,  on  the  other  hand,  we 
purposely  accelerate  respiration  to  any  great  degree,  the  exertion 
soon  becomes  too  fatiguing  for  continuance,  and  the  movements 
return  to  their  normal  standard. 

Cause  of  respiration.  —  The  nervous  impulses  which  cause  the 
contractions  of  the  respiratory  muscles  are  entirely  dependent  on 
the  nervous  system,  especially  that  part  known  as  the  respiratory 
centre,  which  is  located  in  the  medulla  oblongata.  Efferent  nerves 
from  the  respiratory  centre  travel  down  the  spinal  cord  and  end 
at  different  levels,  where  they  connect  with  the  fibres  of  the  pneu- 
mogastric  and  sympathetic  nerves  that  are  distributed  in  the  lung 
tissue.  Afferent  nerves  lead  from  these  different  levels  to  the  res- 
piratory centre. 

The  consensus  of  opinion  at  the  present  time  seems  to  be  that 
the  action  of  the  respiratory  centre  is  automatic,  but  that  the  rate 
and  rhythm  of  the  respiratory  movements  is  controlled  (1)  by 
the  pneumogastric  nerve,  and  (2)  by  the  chemical  condition  of  the 
blood. 


244  ANATOMY  FOR  NURSES  [Chap.  XIII 

(1)  The  fibres  from  the  pneumogastric  nerve  are  of  two  kinds : 
(a)  inspiratory  fibres  which  tend  to  increase  the  rate  of  respiration, 
and  (6)  expiratory  fibres  which  check  the  action  of  the  inspiratory 
set.  The  inspiratory  fibres  are  stimulated  to  action  when  the 
lung  collapses  ;   the  expiratory  when  the  lung  expands. 

(2)  The  respiratory  centre  shows  a  specific  irritabihty  for  carbon 
dioxide,  and  an  increased  amount  of  carbon  dioxide  in  the  blood  acts 
as  a  stimulus,  increasing  the  rate  and  depth  of  the  respirations,  so 
that  the  lungs  are  more  thoroughly  ventilated.  Increased  activ- 
ity, or  any  abnormal  condition  that  increases  the  oxidation  of  the 
tissues,  naturally  results  in  an  increased  production  of  carbon 
dioxide,  and  an  increase  in  the  rate  and  depth  of  the  respirations. 
On  the  other  hand,  an  excess  of  oxA'gen  in  the  blood  may  cause  a 
condition  known  as  physiological  apncea,  i.e.  where  the  blood  is 
so  rich  in  oxj'gen  and  poor  in  carbon  dioxide  that  a  respiratory 
act  is  unnecessary. 

Reflex  stimulation  of  the  respiratory  centre.  —  Every  one  must 
have  noticed  that  the  respiratory  movements  are  affected  by 
stimulation  of  the  sensory  nerves.  Strong  emotion,  sudden  pain, 
or  a  dash  of  cold  water  on  the  skin  produce  changes  in  the  rate  of 
the  respirations.  It  is  assumed,  therefore,  that  the  respiratory 
centre  is  in  connection  with  the  sensory  fibres  of  all  the  cranial 
and  spinal  nerves. 

Cause  of  the  first  respiration.  —  The  immediate  cause  of  the 
first  respiratory  effort  is  closely  connected  with  the  cause  of  the 
activity  of  the  respiratory  centre  during  life.  The  stimulus  is 
supposed  to  come  from  (1)  the  increased  amount  of  carbon 
dioxide  in  the  blood,  due  to  the  cutting  of  the  cord ;  and 
(2)  the  sensory  nerves  of  the  skin,  due  to  cooler  air,  handling,  etc. 
During  intrauterine  life  the  foetus  receives  its  supply  of  oxj'gen 
from  the  blood-vessels  of  the  umbilical  cord,  which  connect  with 
the  placenta.  The  lungs  are  in  a  collapsed  condition  and  contain 
no  air.  The  walls  of  the  air-sacs  are  in  close  contact,  and  the  walls 
of  the  smaller  bronchial  tubes,  or  bronchioles,  touch  one  another 
When  the  chest  ex-pands  with  the  first  breath  taken,  the  inspired 
air  has  to  overcome  the  adhesions  existing  between  the  walls  of  the 
bronchioles  and  air-sacs.  The  force  of  this  first  inspiratory  effort, 
spent  in  opening  out  and  unfolding,  as  it  were,  the  inner  recesses 
of  the  lungs,  is  considerable.     In  the  succeeding  expiration,  most  of 


Chap.  XIII]  RESPIRATORY  SYSTEM  245 

the  air  introduced  by  the  first  inspiration  remains  in  the  lungs,  suc- 
ceeding breaths  unfold  the  lungs  more  and  more,  until  finally 
the  air-sacs  and  bronchioles  are  all  opened  up  and  filled  with 
air.  The  lungs  thus  once  filled  with  air  are  never  completely 
emptied  again  until  after  death. 

Frequency  of  respiration.  —  Each  respiratory  act  in  the  adult 
is  ordinarily  repeated  about  eighteen  times  per  minute.  This 
rate  may  be  increased  by  muscular  exercise,  emotion,  etc.  Any- 
thing that  affects  the  heart-beat  will  have  a  similar  effect  on  the 
respirations.  The  ratio  to  the  pulse  is  about  1  to  4  in  health. 
Age  has  a  marked  influence.  The  average  rate  in  the  newly  born 
infant  has  been  found  to  be  forty-four  per  minute,  and  at  the  age 
of  five  years,  twenty-six  per  minute.  It  is  reduced  between  the 
ages  of  fifteen  and  twenty  to  the  normal  standard. 

Respiratory  sounds.  —  The  entry  and  exit  of  the  air  are  ac- 
companied by  respiratory  sounds  or  murmurs.  These  murmurs 
differ  as  the  air  passes  through  the  trachea,  the  larger  bronchial 
tubes,  and  the  bronchioles.  They  are  variously  modified  in  lung 
disease,  and  are  then  often  spoken  of  under  the  name  of  "  rales." 
In  labored  breathing  the  contraction  of  the  respiratory  muscles 
not  usually  brought  into  play,  such  as  the  muscles  of  the  throat 
and  nostrils,  becomes  very  marked. 

Effects  of  respiration  upon  the  blood.  —  While  the  blood  is 
passing  through  the  pulmonary  capillaries,  the  following  changes 
take  place :  (1)  it  loses  carbon  dioxide ;  (2)  it  gains  oxygen, 
which  combines  with  the  reduced  haemoglobin  of  the  red  corpuscles 
and  turns  it  into  oxyhsemoglobin,  and  as  a  result  of  this  the  crim- 
son color  shifts  to  scarlet ;    (3)  the  temperature  is  slightly  reduced. 

Capacity  of  the  lungs.  —  As  the  lungs  are  not  emptied  at 
each  expiration,  neither  are  they  filled.  If  filled  to  their  utmost, 
they  can  hold  a  little  more  than  one  gallon  (4500  c.c.)  of  air. 
This  total  is  divided  as  follows  :  — 

(1)  Tidal.  (3)  Reserve. 

(2)  Complementary.  (4)  Residual. 

Tidal  air  is  the  air  introduced  with  every  ordinary  inspira 
tion. 

Complementary  air  is  the  excess  over  the  tidal  air  which  may 
be  introduced  during  a  forced  inspiration. 


246 


ANATOMY  FOR  NURSES 


[Ch.\p.  XII 1 


Reserve  air  is  the  amount  of  air  in  addition  to  the  tidal  air 
one  can  expel  from  the  lungs  in  a  forced  expiration. 

Residual  air  is  the  air  remaining  in  the  lungs  after  the  most 
powertul  cxi)iration. 

The  vital  capacity  is  the  sum  of  the  tidal,  complementary, 
and  reserve  airs  added  together.  It  equals  about  225  cubic 
inches  (3700  cc). 

It  is  not  correct  to  think  of  the  residual  air  in  the  lungs  as 
stationary,  for  the  air  is  being  constantly  moved  and  renewed. 
This  movement  is  maintained  by:  (1)  the  alternate  expansion  and 
collapse  of  the  lungs  in  respiration,  (2)  the  convection  currents 
due  to  the  differences  in  temperature  between  the  inspired  air  and 
the  residual  air,  (3)  the  pulsation  of  the  arteries,  and  (4)  the 
difference  in  the  proportion  of  carbon  dioxide  and  ox^'gen  in  the 
inspired  air  and  residual  air.  This  fourth  factor  is  also  responsible 
for  the  interchange  of  gases  between  the  air  in  the  air-sacs  and  the 
blood  in  the  capillaries.  The  reason  is  that  the  blood  contains 
more  carbon  dioxide  and  less  oxygen  than  the  air  in  the  alveoli, 
and  the  tendency  of  gases  is  always  to  mix  in  uniform  proportions. 

The  effects  of  respiration  upon  the  air  outside  the  body.  —  AYith 
every  inspiration  a  well-grown  man  takes  into  his  lungs  about 
30  cubic  inches  (500  cc.)  of  air.  The  air  he  takes  in  differs  from 
the  air  he  gives  out  mainly  in  three  particulars  :  — 

1.  ^Vhatever  the  temperature  of  the  external  air,  the  expired 
air  is  nearly  as  hot  as  the  blood  ;  namely,  of  a  temperature  between 
98°  and  100°  F.  (36.7  and  37.8°  C). 

2.  However  dry  the  external  air  may  be,  the  expired  air  is 
quite,  or  nearly,  saturated  with  moisture. 

3.  The  air  when  breathed  loses  about  one-fourth  of  its  ox\'gen 
and  increases  the  carbon  dioxide  an  hundred  fold;  the  quantity 
of  nitrogen  is  changed  little,  if  any.  To  be  exact,  the  air  loses  4.94 
volumes  of  oxygen  and  gains  4.38  volumes  of  carbon  dioxide. 
Thus :  — 


Inspired  air 
Expired  air 


Oxygen 

Carbon  Dioxide 

Nitrogen 

20.96 
16.02 
4.94  loss 

0.04 
4.38 
4.34  gain 

79 

79 

0 

Chap.  XIII]  RESPIRATORY   SYSTEM  247 

In  addition  the  expired  air  contains  a  certain  amount  of  organic 
matter  which  comes  principally  from  the  mouth  and  particles  of 
food  left  in  the  mouth. 

Ventilation. — Since  at  every  breath  the  external  air  loses  ox;y'gen, 
gains  carbon  dioxide,  and  a  certain  amount  of  organic  matter,  it 
was  formerly  taught  that  the  general  discomfort,  headache,  and 
languor  that  result  from  staying  in  a  badly  ventilated  room  were 
due  to  the  increase  in  carbon  dioxide,  and  the  poisonous  effects  of 
the  organic  matter.  The  results  of  many  experiments  seem  to 
prove  that  people  can  become  so  accustomed  to  a  low  percentage 
of  oxygen  and  a  high  percentage  of  carbon  dioxide  that  they 
suffer  little  discomfort,  and  the  organic  matter  is  not  poisonous, 
though  when  present  in  any  amount  it  causes  disagreeable  odors 
and  makes  the  air  stuffy.  It  is  now  thought  that  the  injurious 
effects  of  remaining  in  a  badly  ventilated  room  are  due  to  inter- 
ference with  the  heat-regulating  mechanism  of  the  body.  The  air 
is  heated  to  a  high  temperature  and  becomes  saturated  with  watery 
vapor.  Both  of  these  conditions  prevent  loss  of  heat  from  the 
body  and  produce  a  fever  temperature.  Even  when  these  condi- 
tions exist  it  has  been  found  that  moving  the  air,  i.e.  keeping  it 
in  circulation  even  without  renewing  it,  has  a  stimulating  effect 
and  lessens  discomfort.  Because  of  these  facts  we  are  now  taught 
that  the  maintenance  of  proper  air  conditions  must  be  based  (1)  on 
the  normal  composition  of  the  air  as  regards  ox;^^gen  and  carbon 
dioxide,  (2)  on  the  temperature,  and  (3)  on  the  degree  of  humid- 
ity. Any  system  of  ventilation  that  is  based  solely  on  the  first 
condition,  and  neglects  to  take  into  account  the  second  and  third 
is  sure  to  prove  unsatisfactory. 

ABNORMAL  TYPES   OF  RESPIRATION 

Dyspnoea.  —  The  word  dyspnoea  means  difficult  breathing. 
It  is  caused  by  (1)  an  increase  in  the  percentage  of  carbon  dioxide 
in  the  blood,  (2)  a  decrease  in  the  ox;\^gen,  and  (3)  any  condition 
that  stimulates  the  sensory  nerves  and  causes  pain  in  the  lungs. 

Hyperpnoea.  —  The  word  hyperpnoea  means  excessive  breathing 
and  is  applied  to  the  initial  stages  of  dyspnoea,  when  the  respira- 
tions are  simply  increased. 

Apnoea.  —  The  word  apnoea  means  a  lack  of  breathing. 


248  ANATOMY   FOR  NURSES  [Chap.  XIII 

Chejme-Stokes  Respirations.  —  This  is  a  type  of  respirations 
which  was  first  described  by  the  two  physicians  whose  names  it 
bears.  It  appears  in  two  forms:  (1)  the  respirations  increase  in 
force  and  frequency  up  to  a  certain  point,  and  then  gradually  de- 
crease until  they  cease  altogether,  and  there  is  a  short  period  of 


Fig.  146.  —  Stethograph  Tracing  of  Cheyne-Stokes  Respirations  in  a 
Man.     The  time  is  marked  in  seconds.      (Halliburton.) 

apnoea,  then  the  respirations  recommence  and  the  cycle  is  repeated. 
(2)  The  respirations  increase  in  force  and  frequency  up  to  a  certain 
point,  then  cease,  and  the  period  of  apnoea  intervenes,  without 
the  gradual  cessation  of  the  respirations.  This  condition  is  asso- 
ciated with  disease  of  the  kidney,  brain,  or  heart.  The  cause  is 
not  settled,  but  it  is  of  bad  prognosis  and  generally  indicates  a 
fatal  termination. 

(Edematous  Respiration.  —  When  the  air  cells  become  in- 
filtrated with  fluid  from  the  blood,  the  breathing  becomes  oedema- 
tous  and  is  recognized  by  the  moist,  rattling  sounds,  called  rales, 
that  accompany  each  inspiration.  It  is  a  serious  condition 
because  it  interferes  with  aeration  of  the  blood  and  often  results  in 
asphyxia. 

Asphyxia.  —  This  condition  is  usually  the  sequel  to  severe  dysp- 
noea and  oedematous  respiration.  It  is  produced  by  any  condition 
that  causes  prolonged  interference  with  the  aeration  of  the  blood. 
After  death  from  asph\ocia  it  will  be  found  that  the  right  side  of 
the  heart,  the  ])ulmonary  arteries  and  the  systemic  veins  are  over- 
loaded, and  the  left  side  of  the  heart,  the  pulmonary  veins,  and  the 
systemic  arteries  are  empty. 


Chap.  XIII]  RESPIRATORY  SYSTEM  249 

MODIFIED   RESPIRATORY  MOVEMENTS 

Various  emotions  may  be  expressed  by  means  of  the  respira- 
tory apparatus. 

Sighing  is  a  deep  and  long-drawn  inspiration,  followed  by 
a  sudden  expiration. 

Yawning  is  an  inspiration,  deeper  and  longer  continued  than 
a  sigh,  drawn  through  the  widely  open  mouth,  and  accompanied 
by  a  peculiar  depression  of  the  lower  jaw. 

Hiccough  is  caused  by  a  sudden  iiispiratory  contraction  of 
the  diaphragm;  the  glottis  suddenly  closes  and  cuts  off  the 
column  of  air  just  entering,  which,  striking  upon  the  closed 
glottis,  gives  rise  to  the  characteristic  sound. 

Sobbing  is  a  series  of  convulsive  inspirations  during  which  the 
glottis  is  closed,  so  that  little  or  no  air  enters  the  chest. 

Coughing  consists,  in  the  first  place,  of  a  deep  and  long-drawn 
inspiration  by  which  the  lungs  are  well  filled  with  air.  This 
is  followed  by  a  complete  closure  of  the  glottis,  and  then  comes 
a  forcible  and  sudden  expiration,  in  the  midst  of  which  the  glottis 
suddenly  opens,  and  thus  a  blast  of  air  is  driven  through  the  upper 
respiratory  passages. 

Sneezing  consists  of  a  deep  inspiration,  followed  by  a  sudden 
and  forced  expiration,  which  directs  the  air  through  the  nasal 
passages. 

Laughing  consists  essentially  in  an  inspiration,  followed  by 
a  whole  series  of  short,  spasmodic  expirations,  the  glottis  being 
freely  open  during  the  whole  time,  and  the  vocal  cords  being 
thrown  into  characteristic  vibrations. 

Crying  consists  of  the  same  respiratory  movements  as  laugh- 
ing; the  rhythm  and  the  accompanying  facial  expressions  are, 
however,  different,  though  laughing  and  crying  often  become 
indistinguishable. 

Speaking  consists  of  a  voluntary  expiration  and  the  vibration 
of  the  vocal  cords  as  the  air  passes  over  them. 


250 


ANATOMY  FOR   NURSES  [Chap  XIII 


Respiration  is  dependent  upon 
prise  the  respiratory  system, 
these  organs. 


Function 


External 
nose 


Nose 


Respiratory 
System 


Larynx 


Internal 

cavities,  or  ' 
nasal  fossae 


SUMMARY 

the  proper  functioning  of  organs  that  corn- 
Air  passes  through  the  nose  or  mouth  to 

Special  organ  of  the  sense  of  smell. 
Passageway  for  entrance   of   air  to   the 

respiratory  organs. 

Framework  of  bone  (nasal)  and  cartilage. 

Covered  with  skin,  hned  with  mucous 

membrane    known    as    pituitary,    or 

Schneiderian. 

Xostrils  are  oval-shaped  openings  on  under 

siu-face,  separated  by  a  partition. 
Extend  from  nostrils  to  the  pharjTix. 
Two  wedge-shaped  ca\'ities. 
'  2  palate. 
2  maxillae. 
1  ethmoid. 

1  sphenoid. 

2  nasal. 


Formed  bv  < 


2  turbinated, 
and  pro- 
cesses of  - 
the    eth 
moid 


Superior 
meatus. 

Middle 
meatus. 

Inferior 
meatus. 


Advantages 
of  nasal 
breathing 

Communicat- 
ing sinuses 


JL^  vomer. 

11  bones, 
r  Warmed. 
Air         <  ^Moistened. 
[  Fihered. 

1.  Frontal. 

2.  Ethmoidal. 

3.  Maxillar}'  or  Antrums  of  Highmore. 

4.  Sphenoidal. 


1.  Larj'nx.  3.  Bronchi. 

2.  Trachea.  4.  Lungs. 

Triangular  box  made  up  of  nine  pieces  of  cartilage. 

Situated  between  the  tongue  and  trachea. 

Contains  vocal  cords. 

SUt  or  opening  between  cords  called  glottis,  which  is  pro- 
tected by  leaf-shaped  lid  called  epiglottis. 

Connected    with    external  f  Mouth, 
air  by  I  Nose. 


Chap.  XIII] 


SUMMARY 


251 


Voice  . 


Trachea 


Bronchi 


Lungs 


Produced  by  vibrations  of  vocal  cords. 

(  Pharynx. 
Resonating  cavities  <  Mouth. 

I  Nasal  cavities. 
Lower  pitch  of  male  voice  is  due  to  greater  length  of  vocal 

cords. 
Fibrous  and  muscular  tube,  4^  in.  long. 
Strengthened  by  C-shaped  f  Complete  in  front, 
hoops  of  cartilage  I  Incomplete  behind. 

In  front  of  oesophagus. 
Extends  from  larynx  to  third  thoracic  vertebra,  where  it 

divides  into  two  bronchi. 
Right  and  left  —  structure  similar  to  trachea. 

r  1  in.  long. 
Right  I  f  in.  wide. 

I  Almost  horizontal. 
[■  2  in.  long. 
Left  <  f  in.  wide. 

I  Almost  vertical. 
Divide  into  innumerable  bronchial  tubes  or  bronchioles. 
Location  —  Occupy  all  of  the  cavity  of  the  thorax  that  is 
not  taken  up  by  the  heart,  blood-vessels,  lymphatics, 
and  oesophagus. 

Outer  surface  convex  to  fit  in   concave 

cavity. 
Base  concave  to  fit  over  convex  diaphragm. 
>  Apex  rises  half  an  inch  above  the  clavicle. 
Hilum   or   depression   on   inner   surface 
gives  passage  to  bronchi,  blood-vessels, 
IjTiiphatics,  and  nerves, 
f  Three  lobes  —  larger,    heavier,    broader, 
I     shorter. 

/  Two   lobes  —  smaller,   narrower,  longer, 
I     front  border  deeply  indented. 
'  Hollow,  spongy  organs.     Consist  of  bron- 
chial tubes — infundibula — alveoli,  also 
blood-vessels,  lymphatics,  and   nerves 
held  together  by  connective  tissues. 
Blood  for  aeration. 
Accompany  bronchial  tubes. 
Pulmonary  J  Plexus  of  capillaries  around 
artery  alveoli. 

Returned     by     pulmonary 
veins. 
Bronchial  arteries — supply  lung  substance. 

1.  Branches  from  the  sympathetic  system. 

2.  Branches  from  the  pneumogastric. 


Cone-shaped 
organs 


Right 


Left 


Anatomy 


Blood-vessels 


Nerves 


252 


ANATOMY  FOR  NURSES  [Chap.  XIII 


PleuTi 


Mediastinum 


Closed  sac.    Envelops  lungs,  but  they  are  not  in  it. 


Two  layers 


(■  Visceral  —  next  to  lung 


V1&- 


1  Moistened 


1     by  serum. 


Respiration 


Ftmction 


Mechanism 
of    Inspira- 
tion and 
Expiration 


<  Parietal  —  outside    of 
I     ceral 
Function  —  To  lessen  friction. 

■  Space  between  pleural  sacs.    Extends  from  sternum  to 
spinal  column. 

Increase  the  amount  of  oxj^gen. 

Decrease  the  amount  of  carbon  dioxide. 

Help  to  maintain  temperature. 

Help  to  eliminate  waste. 

Absorption  of  oxygen  from  air  by  circulate* 
ing  blood  in  the  lungs. 

Absorption  of  carbon  dioxide  from  circu- 
lating blood  by  the  air  in  the  air  sacs. 

Inspiration  —  Process  of  taking  air  into 
lungs. 

Expiration  —  Process  of  expelling  air  from 
lungs. 

Absorption  of  oxygen  from  the  blood  by 
all  the  cells  of  the  body. 

Absorption  of  carbon  dioxide  from  all  the 
cells  by  the  blood. 

of 


External 


Internal 


Inspiration 


Chest  cavity  enlarged 


'  Elevation 

ribs. 
Descent    of 
diaphragm. 


Cause  of 
Respiration 


Expiration 


Chest  cavity  made  smaller 


Lungs  expand. 

Air  rushes  in  through  trachea  and  bronchi. 

Inspiratory 
muscles  re- 
lax. 
Recoil  of  elas- 
tic thorax. 
Recoil  of  elas- 
tic lungs. 
Air  forced  out  through  trachea. 

1 .  Respiratory  centre  —  Action  is  automatic.    Assumed 

to  be  in  eonnection  with  all  the  cranial  and  spinal 
nerves. 

2.  Pneumogastric  nerves. 

3.  Sympathetic  nerves.        ' 

Inspiratory  —  tend 


Rate  and  rhythm 
controlled  by 


Pneumogastric  ^ 
nerves 


to  increase  rate. 
Expiratory  —  check 
the  action  of  the 
inspiratory  set. 
Carbon  dioxide  content  of  blood. 


Chap.  XIII] 


SUMMARY 


253 


Cause  of 
First  Respi- 
ration 


Respiratory 
Rate 

Effect  of 
Respiration 
upon  the 
Blood 


Capacity  of 
Lungs 


Movement  of 
Residual  Air 
maintained  by 

Effect  of 
Respiration 
upon  the 
Air  outside 
the  Body 


Proper  Ven- 
tilation 


'  1.  Increased  amount  of  carbon  dioxide  due  to  cutting  of 

the  cord. 
2.  Reflex,  due  to  stimulation  of  the  sensory  nerves  of  the 
skin. 


IS  times  per  minute. 
Ratio  to  pulse  1  to  4. 


Influenced  by 


Muscular  exercise. 
Emotion. 
Heart-beat. 
I  Age. 


1.  Loses  carbon  dioxide. 

_,    „   .  [  Oxyhaemoglobin. 

2.  Gams  oxvgen  i  „      ,  ^      , 

'  I  Scarlet  color. 

3.  Temperature  is  slightly  reduced. 

r  Tidal 
A  little  more  than 
1   gallon  of  air  ■ 
(4500  c.c.) 


Complemen- 
tary 
Reserve 
Residual 


►  Vital  capacity  3700  c.c. 


Abnormal 
Types 


'  1.  Alternate  expansion  and  collapse  of  lungs. 

2.  Convection  currents. 

3.  Pulsation  of  the  arteries. 

4.  Diffusion  of  gases. 

1 .  Temperature  increased.     Expired  air  is  as  hot  as  blood. 

2.  Moisture  increased.     Expired  air  is  saturated  with 

moisture. 

3.  Oxygen  decreased  by  4.94  parts  in  a  hundred. 

4.  Carbon  dioxide  increased  by  4.38  parts  in  a  hundred. 

5.  Organic  matter  gained. 

1.  Composition  of  air  as  regards  oxygen  and  carbon 

dioxide. 

2.  Proper  temperature. 

3.  Degree  of  humidity. 

'  Dyspnoea  —  difficult  breathing. 
Hyperpnoea  —  excessive  breathing. 
Apnoea  —  lack  of  breathing. 

1.  Respirations  increase  in  force  ana 
frequency,  then  gradually  de- 
crease   and    stop.     Cycle    re- 
-  Cheyne-Stokes        \  peated. 

.  Respirations  increase  in  force  and 
frequency  up  to  a  certain  point, 
then  stop.     Cycle  repeated. 
(Edematous  —  air   cells   filled  with  fluid,  hence  moist, 

rattling  sounds. 
Asphyxia  —  oxygen  starvation. 


CHAPTER   XIV 

THE  DIGESTIVE  SYSTEM:    ALIMENTARY  CANAL  AND  ACCESSORY 

ORGANS 

Digestion  is  the  process  by  means  of  wliich  the  food  we  take 
into  our  mouths  is  transformed  into  a  condition  of  solution  or 
emulsion  suitable  for  absorption  into  the  blood.  The  organs  in 
which  the  food  is  contained  while  undergoing  digestion  as  well  as 
the  organs  which  assist  in  the  process  are  grouped  together  and 
called  the  digestive  system. 

THE  DIGESTIVE  SYSTEM 

The  digestive  system  consists  of  the  alimentary  canal  and 
the  accessory  organs :  (1)  the  salivary  glands,  (2)  the  tongue, 
(3)  the  teeth,  (4)  the  pancreas,  and  (5)  the  liver. 

ALIMENTARY  CANAL 

The  alimentary  canal  is  a  musculo-membranous  tube  extending 
from  the  mouth  to  the  anus.  It  is  about  twenty-eight  feet  long 
and  the  greater  part  of  it  is  coiled  up  in  the  cavity  of  the  abdomen. 
The  diameter  of  the  tube  is  by  no  means  uniform,  being  consider- 
ably dilated  in  certain  parts  of  its  course.  It  is  composed  of  three 
coats,  the  serous  coat  being  absent  from  the  mouth,  to  where  it 
passes  through  the  diaphragm,  and  of  four  coats  in  the  abdominal 
cavity.     These  coats  are :  — 

(1)  The  mucous  j  Both  described 

(2)  The  areolar,  or  sub-mucous  [  in  Chapter  VIII. 

(3)  The  muscular  coat  is  composed  for  the  most  part  of  un- 
striped  muscular  fibres,  the  layers  of  which  are  disposed  in  various 
ways,  the  most  general  arrangement  being  in  a  longitudinal  and 
circular  direction.  By  the  alternate  contraction  and  relaxation 
of  fibres  arranged  in  this  fashion  (the  contractions  starting  from 
above),  the  contents  of  the  tube  are  propelled  from  above  dowTi- 
ward. 

254 


Chap.  XIV] 


THE   DIGESTIVE  SYSTEM 


255 


(4)  The  serous  coat  is  derived  from  the  peritoneum. 

The  peritoneum.  —  This  is  a  double  membrane,  the  outer  or 
parietal  layer  of  which  lines  the  inner  surface  of  the  abdominal  and 
pelvic  cavities,  and  the  inner  or  visceral  layer  is  reflected  back  over 
the  contained  organs.  The  arrangement  of  the  peritoneum  is 
very  complex,  for  several  elongated  sacs  and  double  folds  extend 
from  it,  to  pass  in  between  and  either  wholly  or  partially  surround 
the  viscera  of  the  abdomen  and  pelvis.  One  important  fold  is 
the  omentum,  which  hangs  like  a  curtain  in  front  of  the  stomach 
and  the  intestines ;  another  is  the  mesentery,  which  surrounds  the 
greater  part  of  the  small  intestine.  The  posterior  portion  of  the 
mesentery  is  gathered  into  folds  which  are  attached  to  the  spine 
and  serve  to  hold  the  intestines  in  place. 

Functions  of  the  peritoneum.  —  Like  all  serous  membranes 
the  peritoneum  serves  to  prevent  friction  between  contiguous 
organs  by  secreting  serum  which  acts  as  a  lubricant.  It  also  serves 
to  hold  the  abdominal  and  pelvic  organs  in  position,  to  unite  and 
separate  these  organs,  and  supports  numerous  nerves  and  blood- 
vessels. The  omentum  usually  contains  fat,  and,  in  addition  to 
the  usual  functions,  serves  to  keep  the  organs  it  covers  warm. 

Divisions  of  the  alimentary  canal.  —  For  convenience  of  descrip- 
tion, the  alimentary  canal  may  be  divided  into :  — 

Mouth,  containing  tonsils,  tongue,  salivary  glands,  and  teeth. 

Pharynx. 

(Esophagus. 
Stomach. 

r  Duodenum. 
Small  or  thin  intestine    <  Jejunum. 

[  Ileum. 

f  Caecum. 


Large  or  thick  intestine  • 


f  Ascending. 
Colon      \  Transverse. 

i  Descending. 
Rectum. 


MOUTH,  OR  BUCCAL  CAVITY 

The  mouth  is  a  nearly  oval-shaped  cavity  with  a  fixed  roof 
anteriorly,  a  flexible  roof  posteriorly,  and  a  movable  floor.     It 


256 


ANATOMY  FOR  NURSES 


[Chap.  XIV 


is  bounded  in  front  l)y  the  lips,  on  the  sides  by  the  cheeks,  below 
by  the  tongue,  and  above  by  the  palate. 

The  palate.  —  The  palate  consists  of  a  hard  portion  in  front 
formed  by  bone,  covered  by  mucous  membrane,  and  of  a  soft 
portion  behind  containing  no  bone.  The  hard  palate  forms  the 
partition  between  the  mouth  and  nose ;  the  soft  palate  arches 
backward  and  hangs  like  a  curtain  between  the  mouth  and 
the  pharynx.  Hanging  from  the  middle  of  its  lower  border  is  a 
pointed  portion  of  the  soft  palate  called  the  uvula  (little 
grape). 

Palatine  arches.  —  From  the  base  of  the  uvula  on  either  side 
there  passes  a  curved  fold  of  muscular  tissue  covered  by  mucous 
membrane,  which  shortly  after  leaving  the  uvula  is,  as  it  were, 

split   into    two    pillars,   the 
^%  one   gcung   outward,   down- 

I    %  ward,  and  forward,  passing 

to  the  side  of  the  tongue, 
the  other  outward,  down- 
ward, and  backward  to  the 
side  of  the  pharynx.  These 
pillars  are  known  respec- 
tively as  the  anterior  and  the 
posterior  pillars  of  the  fauces. 
Tonsils.  —  In  the  lower 
part  of  the  triangular  space 
between  the  anterior  and 
posterior  pillars  on  either 
side  lie  the  small  masses  of 
lymphoid  tissue  called  ton- 
sils. They  consist  of  a  col- 
lection of  lymph  nodules 
held  together  by  a  distinct 
capsule  and  covered  on  their 
ex-posed  surface  by  mucous 
membrane. 

Function.  —  The  function  of  the  tonsils  is  imperfectly  under- 
stood. They  may  be  a  source  of  lymphocytes  and  leucocytes,  or 
they  may  act  as  filters  and  prevent  the  entrance  of  microorgan- 
isms.    Inflammation  of  the  tonsils  is  called  tonsillitis. 


Fig.  147.  —  The  Soft  P.\late  and 
Tonsillar  Regions.     (Gcrrish.) 


Chap.  XIV] 


THE   DIGESTIVE  SYSTEM 


257 


The  palate,  uvula,  palatine  arches,  and  tonsils  are  plainly  seen 
if  the  mouth  is  widely  opened  and  the  tongue  depressed. 

The  fauces  is  the  name  given  to  the  aperture  leading  from  the 
mouth  into  the  pharynx,  or  throat  cavity. 

The  tongue.  —  The  tongue  ^  is  the  special  organ  of  the  sense  of 
taste  and  assists  in  speech.  It  has  also  to  be  considered  with  ref- 
erence to  digestion,  (1)  because  stimulation  of  the  nerves  of  the 
sense  of  taste  start  the  secretion  of  digestive  juices,  (2)  it  assists  in 
swallowing,  and  (3)  the  follicles  at  the  back  of  the  tongue  secrete 
mucus,  which  lubricates  the  food  and  makes  swallowing  easier. 

The  salivary  glands.  —  The  mucous  membrane  lining  the 
mouth  contains  many  minute  glands  consisting  of  just  one  cell. 
These  are  called  goblet  cells  and  pour  their  secretion  upon  its 
surface,  but  the  chief 
secretion  of  the  mouth 
is  supplied  by  the 
salivary  glands,  which 
are  three  pairs  of  com- 
pound saccular  glands 
called  the  parotid,  sub- 
maxillary, and  sub- 
lingual, respectively. 
Each  parotid  gland  is 
placed  just  under  and 
in  front  of  the  ear ;  its 
duct  passes  forward 
along  the  cheek,  until 
it  opens  into  the  in- 
terior of  the  mouth 
opposite  the  second 
molar  tooth  of  the 
upper  jaw.  The  submaxillary  and  sublingual  glands  are  situ- 
ated below  the  jaw  and  under  the  tongue,  the  submaxillary 
being  placed  further  back  than  the  sublingual.  Their  ducts  open 
in  the  floor  of  the  mouth  beneath  the  tongue.  The  secretion  of 
these  salivary  glands,  mixed  with  that  of  the  small  glands  of  the 
mouth,  is  called  saliva. 

The  teeth.  —  The  semicircular  borders  of  the  upper  and  lower 


Fig.  148.  —  The  Salivary  Glands. 


'  A  detailed  description  of  the  tongue  will  be  found  in  Chapter  XX. 
B 


258 


ANATOMY  FOR  NURSES 


[Chap.  XIV 


jaw-bones  (the  alveolar  processes)  contain  sockets  for  the  recep- 
tion of  the  teeth.  A  dense  insensitive  fibrous  membrane  covered 
by  smooth  mucous  membrane  —  the  gums  —  covers  these  pro- 
cesses and  extends  a  little  way  into  each  socket.  These  sockets 
are  lined  by  periosteum,  which  connects  with  the  gums  and  serves 


POLP-CAVITY \ 


Fig.  149.  —  Section  cf  Hu.\ian    Molar   Tooth.     Magnified.     (Dalton.) 

(1)  to  attach  the  teeth  to  their  sockets,  and  (2)  as  a  source  of  nour- 
ishment. 

Each  tooth  consists  of  three  portions:  (1)  the  root,  consisting 
of  one  or  more  fangs  contained  in  the  socket ;  (2)  the  crotvn, 
which  projects  beyond  the  level  of  the  gums;  and  (3)  the  neck 
or  constricted  portion  between  the  root  and  the  crown,  which  is 
enveloped  by  the  gum. 

Each  tooth  is  composed  principally  of  dentine,  which  gives  it 
shape  and  encloses  a  cavity,  the  pulp  cavity.  The  dentine  of  the 
crown  is  capped  with  a  dense  layer  of  enamel.  The  dentine  of  the 
root  is  covered  by  cement.  These  three  substances,  enamel, 
dentine,  and  cement,  are  all  harder  than  bone,  enamel  being 
the  hardest  substance  found  in  the  body.  They  are  developed 
from  epithelial  tissue.     The  pulp  cavity  is  just  under  the  crown  and 


Chap.  XIV]  THE   DIGESTIVE  SYSTEM  259 

is  continuous  with  a  canal  that  traverses  the  centre  of  each  root, 
and  opens  by  a  small  aperture  at  its  extremity.  It  is  filled  with 
dental  pulp,  which  consists  of  loose  connective  tissue  holding  a 
number  of  blood-vessels  and  nerves  which  enter  by  means  of  the 
canal  from  the  root. 

There  are  two  sets  of  teeth  developed  during  life :  the  first, 
temporary  or  deciduous ;   and  the  second,  permanent. 

Temporary  teeth.  —  In  the  first  set  are  twenty  teeth,  ten  in  each 
jaw.  The  cutting  of  the  temporary  teeth  begins  usually  at  seven 
months  and  ends  at  about  the  age  of  two  and  one-half  years. ^ 

Permanent  teeth.  —  In  the  second  set  are  thirty-two  permanent 
teeth,  sixteen  in  each  jaw.  During  childhood  the  temporary 
teeth  are  replaced  by  the  permanent.  The  first  molar  usually 
appears  at  six  years  of  age. 

According  to  their  shape  and  use  the  teeth  are  divided  into 
incisors,  canines,  premolars,  and  molars. 

Right  Middle  Left 


Molar  Premolar  Canine  Incisor  Canine  Premolar  Molar 
Upper     ...       3  2  1  4  1  2  3 

Lower     ...       3  2  1  4  1  2  3 

(ColHns.) 

Incisors  are  eight  in  number  and  form  the  four  front  teeth 
of  each  jaw.  They  have  wide,  sharp  edges,  and  are  specially 
adapted  for  cutting  food. 

Canines  are  four  in  number,  two  in  each  jaw.  The  upper 
canines  are  commonly  called  eye-teeth,  the  lower,  stomach  teeth. 
They  have  a  sharp,  pointed  edge  and  are  longer  than  the  incisors. 
In  the  human  animal  they  serve  the  same  purpose  as  the  incisors. 

Premolars  (or  bicuspids)  are  eight  in  number  in  the  permanent 
set,  but  there  are  none  in  the  temporary  set.  There  are  four  in 
each  jaw,  two  being  placed  just  behind  each  of  the  canine  teeth. 

They  are  broad,  with  two  points  or  cusps  on  each  crown  ;  these 
teeth  have  only  one  root,  the  root,  however,  being  more  or  less 
completely  divided  into  two.  Their  function  is  to  cut  and  grind 
food. 

'  The  temporary  teeth  are  usually  cut  in  the  following  order,  the  teeth  of  each 
group  appearing  first  in  the  lower  jaw :  central  incisors,  7th  month ;  lateral  inci- 
sors, 7th  to  10th  month  ;  front  molars,  12th  to  14th  month  ;  canine,  14th  to  20th 
month ;    back  molars,  18th  to  30th  month. 


260  ANATOMY  FOR  NURSES  [Chap.  XIV 

Molars  are  twelve  in  number  in  the  permanent  set,  but  there 
are  only  eight  in  the  temporary  set. 

The  molars,  or  true  grinders,  have  broad  crowns  with  small, 
pointed  projections,  which  make  them  well  fitted  for  crushing  and 
bruising  the  food :  they  each  have  two  or  three  roots.  The  twelve 
molars  do  not  replace  the  temporary  teeth,  but  are  gradually 
added  with  the  growth  of  the  jaws  ;  the  last  or  hindermost  molars 
may  not  appear  until  twenty-one  years  of  age;  hence  called 
"  late  teeth  "  or  "  wisdom  teeth." 

Function.  —  The  teeth  assist  in  the  process  of  mastication  by 
cutting  and  grinding  the  food. 

THE   PHARYNX 

The  pharynx,  or  throat  cavity,  is  a  musculo-membranous  bag 
shaped  somewhat  like  a  funnel,  with  its  broad  end  turned  upward, 
and  its  constricted  end  downward  to  end  in  the  oesophagus. 
It  is  about  four  and  a  half  inches  (113  mm.)  long,  and  lies  behind 
the  nose  and  mouth.  Above,  it  is  attached  to  the  base  of  the 
skull,  and  behind,  to  the  cervical  vertebrae ;  in  front  and  on  each 
side  are  apertures  which  communicate  with  the  nose,  ears,  mouth, 
and  larynx. 

Of  these  apertures  there  are  seven  :  — 

Two  in  front  above,  leading  into  the  back  of  the  nose,  the 
posterior  nares. 

Two,  one  on  either  side  above,  leading  into  the  Eustachian 
tubes,  which  communicate  with  the  ears. 

One  midway  in  front,  the  fauces. 

Two  below,  one  opening  into  the  larynx  and  the  other  into  the 
oesophagus. 

The  mucous  membrane  lining  the  pharynx  is  well  supplied 
with  glands,  and  at  the  back  of  the  cavity  there  is  a  con- 
siderable mass  of  lymphoid  tissue.  During  infancy  and  child- 
hood this  may  increase  to  such  an  extent  that  it  interferes  with 
nasal  breathing.  The  child  is  then  said  to  have  adenoids  and 
is  obliged  to  breathe  through  the  mouth  ;  hence  the  term  "  mouth 
breathers." 

Function.  —  The  muscular  tissue  in  the  walls  of  the  pharynx  is 
of  the  striped  variety,  and  when  the  act  of  swallowing  is  about  to 


Chap.  XIV]  THE  DIGESTIVE  SYSTEM  261 

be  performed,  the  muscles  draw  the  pharyngeal  bag  upward  and 
dilate  it  to  receive  the  food ;  they  then  relax,  the  bag  sinks,  and 
the  other  muscles  contracting  upon  the  food,  it  is  pressed  down- 
ward and  onward  into  the  oesophagus. 

THE  (ESOPHAGUS,   OR  GULLET 

The  oesophagus  is  a  comparatively  straight  tube,  about  nine 
inches  (225  mm.)  long,  which  commences  at  the  lower  end  of  the 
pharynx,  behind  the  trachea.  It  descends  in  front  of  the  spine, 
passes  through  the  diaphragm,  and  terminates  in  the  upper  or 
cardiac  end  of  the  stomach. 

Structure.  —  The  walls  of  the  oesophagus  are  composed  of  three 
coats :  (1)  an  external  or  muscular,  (2)  a  middle  or  areolar,  and 
(3)  an  internal  or  mucous,  coat.  The  fibres  of  the  muscular  coat 
are  arranged  in  an  external  longitudinal  and  in  an  internal  circular 
layer.  Contraction  of  the  outer  layer  produces  dilatation  of  the 
tube;  contraction  of  the  inner,  constriction.  Consequently  this 
arrangement  is  of  importance  in  the  movements  which  carry  the 
food  from  the  pharynx  to  the  stomach.  These  movements  are 
called  peristaltic  and  consist  of  contraction  of  the  longitudinal 
fibres,  followed  by  contraction  of  the  circular  fibres.  The  areolar 
coat  serves  to  connect  the  muscular  and  mucous  coats.  The 
mucous  membrane  is  disposed  in  longitudinal  folds  which  disap- 
pear upon  distention  of  the  tube. 

Function.  — The  oesophagus  serves  (1)  to  connect  the  pharynx 
with  the  stomach,  and  (2)  to  receive  the  food  from  the  pharynx 
and  by  a  series  of  peristaltic  contractions  pass  it  on  to  the 
stomach. 

Regions  of  the  abdomen.  — That  portion  of  the  alimentary 
canal  which  is  below  the  thorax  is  contained  in  the  abdomen. 
For  convenience  of  description,  the  abdomen  may  be  artificially 
divided  into  nine  regions  by  drawing  the  following  arbitrary 
lines :  — 

1.  Draw  a  circular  line  around  the  body  at  the  level  of  the 
tenth  costal  cartilages. 

2.  Draw  another  circular  line  at  the  level  of  the  anterior  superior 
spines  of  the  ilia. 

3.  Draw  a  vertical  line  on  each  side  from  the  centre  of  Poupart's 
ligament  upward. 


262 


ANATOMY   FOR   NURSES 


[Chap.  XIV 


These  lines  are  to  be  eonsidered  as  edges  of  planes  which  divide 
the  abdomen  into  the  following  regions  as  per  illustration. 


HIGHEST  LEVEt 
OF  ILIAC  CRESr 


ANT.    SUP. 
ILIAC  SPINE 


Fig.  150.  —  Region.s  of  the  Abdo.mex.     (Gerrish.) 


Right  Hypochondriac. 
—  The  right  lobe  of  the 
liver  and  the  gall-bladder, 
hepatic  flexure  (right  colic 
flexure)  of  the  colon,  and 
part  of  the  right  kidney. 


Right  Lu.mb.ar.  —  As- 
cending colon,  part  of  the 
right  kidney,  and  some 
convolutions  of  the  small 
intestines. 


Right  Inguinal  (Il- 
iac).—  The  cipcum,  ver- 
miform appendix ;  the 
right  ureter. 


Epiga.sthic  Region.  — 
The  pyloric  end  of  the 
stomach,  left  lobe  of  the 
liver,  the  pancreas,  the 
duodenum,  parts  of  the 
kidneys,  and  the  supra- 
renal capsules. 

Umbilical  Region.  — 
The  transverse  colon,  part 
of  the  great  omentum  and 
mesentery,  transverse  part 
of  the  duodenum,  and 
some  convolutions  of  the 
jejunum  and  ileum,  and 
part  of  both  kidneys. 

Hypogastric  Region. 
—  Convolutions  of  the 
small  intestines,  the  blad- 
der in  children,  and  in 
adults  if  distended,  and 
the  uterus  during  preg- 
nancy. 


Left  Hypochondriac. 
—  The  cardiac  end  of  the 
stomach,  the  spleen  and 
extremity  of  the  pancreas, 
the  splenic  flexure  (left 
colic  flexure)  of  the  colon, 
and  part  of  the  left  kidney. 

Left  Lumbar.  —  De- 
scending colon,  part  of 
the  omentum,  part  of  the 
left  kidney,  and  some  con- 
volutions of  the  small  in- 
testines. 


Left  Inguinal  (Iliac). 
—  Sigmoid  flexure  of  the 
colon  ;    the  left  ureter. 


Chap.  XIV]  THE  DIGESTIVE  SYSTEM  263 

THE  STOMACH 

After  the  oesophagus  perforates  the  diaphragm  it  ends  in  the 
stomach  (gaster),  which  is  the  most  dilated  portion  of  the  ali- 
mentary canal.  It  is  a  hollow  pouch  placed  obliquely  in  the 
left  side  of  the  upper  portion  of  the  abdominal  cavity.^  It  is 
curved  upon  itself,  so  that  below  it  presents  a  long,  rounded 
outline,  called  the  greater  curvature,  and  above,  a  constricted, 
concave  outline,  called  the  lesser  curvature. 

The  greater  curvature  is  directed  to  the  left,  and  the  lesser 
curvature  faces  mostly  to  the  right. 

The  fundus,  or  cardiac,  end  is  the  greater  extremity,  which  pro- 
jects several  inches  to  the  left  of  the  oesophagus  and  is  in  contact 
with  the  spleen.  The  opposite  or  smaller  end  is  called  the  pyloric 
extremity  and  lies  under  the  liver. 

The  central  portion  between  the  fundus  and  pyloric  extremity 
is  called  the  intermediate  region. 

The  stomach  has  necessarily  two  openings :  the  one  leading 
into  the  oesophagus  is  usually  termed  the  cardiac  aperture ; 
the  other,  leading  into  the  small  intestine,  the  pyloric.  Both  the 
cardiac  and  pyloric  apertures  are  guarded  by  strong  circular  bands 
of  muscle  which  are  normally  in  a  state  of  contraction.  By  this 
arrangement,  the  food  is  kept  in  the  stomach  until  it  is  ready  for 
intestinal  digestion,  when  the  circular  fibres  guarding  the  pyloric 
aperture  relax  and  allow  it  to  pass. 

When  distended,  the  stomach  measures  about  fifteen  inches 
(38  cm.)  from  end  to  end  and  about  five  inches  (13  cm.)  antero- 
posteriorly,  and  has  a  capacity  of  about  one  quart.  The  above 
description  applies  to  the  position  and  form  of  the  stomach  when 
normally  filled  with  food,  but  the  student  must  bear  in  mind 
that,  when  empty,  the  stomach  contracts  down  so  as  more  nearly 
to  approach  a  true  cylinder,  the  contraction  and  dilatation 
affecting  more  the  greater  curvature  than  the  lesser.  When 
contracted,  the  stomach  is  shorter  as  well  as  of  lesser  diameter. 

Coats  of  the  stomach.  —  It  has  four  coats :  from  the  out- 
side, (1)  serous,  (2)  muscular,  (3)  submucous  or  areolar,  and 
(4)  mucous. 

(1)  The  serous  coat  is  formed  by  a  fold  of  the  peritoneum.    The 

1  Epigastric  and  left  hypochondriac  region. 


264 


ANATOMY   FOR   NURSES  [Chap.  XIV 


fold  is  slung  over  the  stomach,  in  much  the  same  way  as  we  sling 
a  towel  over  a  clothesline,  and  covers  it  before  and  behind.  The 
anterior  and  posterior  folds  unite  at  the  lower  border  of  the 


Fig.  151.  —  The  Stomach  and  Intestines,  Fkont  View,  the  Great  Omen- 
tum   HAVING    been    removed,    AND    THE    LiVER    TURNED     UP    AND    TO    THE     RiGHT. 

The  dotted  Hue  shows  the  normal  position  of   the   anterior   border  of  the  liver. 
(Gerrish.) 

stomach  and  form  an  apron-like  appendage,  the  omentum,  which 
covers  the  whole  of  the  intestines. 

(2)  The  muscular  coat  of  the  stomach  consists  of  three  layers 
of  unstriped  muscular  tissue :  an  outer,  formed  of  longitudinal 
fibres ;  a  middle,  of  circular ;  and  an  inner,  of  less  well-developed, 
obliquely  disposed  fibres. 


Chap.  XIV]  THE   DIGESTIVE  SYSTEM  265 

(3)  The  submucous,  also  called  the  areolar  coat,  is  loose  and 
vascular.  It  carries  the  nerves  and  vessels  which  go  to  and 
from  the  muscular  and  mucous  coats. 

(4)  The  mucous  coat  is  very  soft  and  thick,  the  thickness  being 
mainly  due  to  the  fact  that  it  is  densely  packed  with  small  tubular 
glands.  It  is  covered  with  columnar  epithelium,  and  in  its  undis- 
tended  condition  is  thrown  into  folds  or  rugae.  The  surface  is 
honeycombed  by  tiny,  shallow  pits,  into  which  the  ducts  or  mouths 
of  the  tubular  glands  open.  The  glands  are  of  two  kinds :  (1)  pep- 
tic, (2)  pyloric.     During  digestion  they  secrete  the  gastric  juice. 

Nerves  and  blood-vessels.  —  The  stomach  is  supplied  with 
nerves  from  the  sympathetic  system,  and  also  with  branches 
from  the  pneumogastric  nerve,  which  comes  from  the  cerebro- 
spinal system.  The  blood-vessels  are  derived  from  the  three 
divisions  of  the  coeliac  axis. 

Function. — The  functions  of  the  stomach  are  (1)  to  connect 
the  oesophagus  with  the  intestine,  (2)  to  hold  the  food  while  it 
undergoes  gastric  digestion,  and  (3)  to  secrete  mucus  and  gastric 
juice. 

THE  SMALL  OR  THIN  INTESTINE^ 

The  small  intestine  extends  from  the  stomach  (pyloric  valve) 
above  to  the  large  intestine  (valve  of  the  colon)  below.  It  is 
a  convoluted  tube  about  twenty  feet  (6.0  m.)  in  length,  and  fills 
the  greater  part  of  the  front  abdominal  cavity.  Its  diameter  at 
the  beginning  is  about  two  inches  (5  cm.),  but  it  gradually  dimin- 
ishes in  size  and  is  hardly  an  inch  (2.5  cm.)  in  diameter  at  its  lower 
end.  The  small  intestine  is  divided  by  anatomists  into  three 
portions :  — 

The  duodenum. 

The  jejunum. 

The  ileum. 

The  duodenum.  —  The  duodenum  is  twelve  fingers'  breadth 
in  length  (eight  inches  or  20  cm.),  and  is  the  widest  part  of  the 
small  intestine.  It  extends  from  the  pyloric  end  of  the  stomach 
to  the  jejunum. 

Beginning  at  the  pylorus,  the  duodenum  at  first  passes  in  a 
direction  upward  and  backward  to  the  under  surface  of  the  liver ; 
it  then  makes  a  complete  bend  and  passes  in  a  direction  downward 


266  ANATOMY   FOR   NURSES  [Chap.  XIV 

in  front  of  the  kidney ;  it  again  turns  in  a  right  angle  direction 
to  the  left  and  passes  horizontally  across  the  front  of  the  ver- 
tebral column.  This  third  portion  of  the  duodenum  lies  retro- 
peritoneally,  so  that  only  its  anterior  aspect  is  covered  by  peri- 
toneum. The  small  intestine  now  passes  forward  so  as  to  leave 
the  posterior  abdominal  wall,  and  becomes  completely  invested 
by  peritoneum  and  has  a  true  mesentery.  The  point  at  which 
it  becomes  completely  invested  by  peritoneum  marks  the  ter- 
mination of  the  duodenum  and  the  beginning  of  the  jejunum. 

The  jejunum. — The  jejunum,  or  empty  intestine,  so  called 
because  it  is  always  found  empty  after  death,  constitutes  about 
two-fifths  of  the  remainder,  or  seven  and  a  half  feet  (2.2  m.),  of 
the  small  intestine,  and  extends  from  the  duodenum  to  the  ileum. 

The  ileum.  — The  ileum,  or  twisted  intestine,  so  called  from  its 
numerous  coils,  constitutes  the  remainder  of  the  small  intestine, 
and  extends  from  the  jejunum  to  the  large  intestine,  which  it  joins 
at  a  right  angle. 

There  is  no  definite  landmark  to  determine  the  point  at  which 
the  jejunum  ceases  and  the  ileum  begins,  although  the  mucous 
membrane  of  the  one  differs  somewhat  from  the  mucous  mem- 
brane of  the  other;  the  change  is  a  gradual  transition,  and  one 
structure  shades  off  into  the  other.  The  lengths  in  feet  as  given 
are  arbitrary,  but  those  usually  accepted. 

Coats  of  the  small  intestine.  —  The  small  intestine  has  four 
coats,  which  correspond  in  character  and  arrangement  with 
those  of  the  stomach. 

(1)  The  serous  coat  furnished  by  the  peritoneum  forms  an  al- 
most complete  covering  for  the  whole  tube  except  for  part  of  the 
duodenum. 

(2)  The  muscular  coat  of  the  small  intestine  has  only  two 
layers:  an  outer,  thiimer  and  longitudinal;  and  an  inner,  thicker 
and  circular.  This  arrangement  is  necessary  for  the  peristaltic 
action  of  the  intestine. 

(3)  The  submucous,  or  areolar  coat,  carries  blood-vessels, 
lymphatics,  and  nerves. 

(4)  The  mucous  coat  is  thick  and  very  vascular. 

ValvulcB  conniventes.  —  About  two  inches  beyond  the  pylorus 
the  mucous  and  submucous  coats  of  the  small  intestine  are  ar- 
ranged in  circular  folds  called  valvulae  conniventes.     Each  of  these 


Chap.  XIV]  THE  DIGESTIVE   SYSTEM 


267 


Fig.    152.  —  Portion  of  Small   Intes- 
tine LAID  OPEN  TO  SHOW  VALVULE  CONNI- 

VENTES.     (Collins.) 


folds  extends  part  of  the  way  around  the  circumference  of  the  in- 
testine.   Unlike  the  rugfe  of  the  stomach,  the  valvulae  conniventes 
do  not   disappear  when  the 
intestine  is  distended.  About 
the  middle  of  the  jejunum 
they   begin    to    decrease    in 
size,  and  in  the  lower  part  of 
the   ileum    they   almost   en- 
tirely disappear.     The  pur- 
pose of  the  circular  folds  is : 
(1)  to  prevent  the  food  from 
passing   through    the    intes- 
tines too  quickly,  and  (2)   to  present  a  greater  surface  for  the 
absorption  of  digested  food. 

J^ilH.  —  Throughout  the  whole  length  of  the  small  intestine  the 
mucous  membrane  presents  a  velvety  appear- 
ance due  to  minute  finger-like  projections 
called  villi.  Each  villus  consists  of  a  central 
lymph  channel  called  a  lacteal,  surrounded 
by  a  network  of  blood  capillaries,  held  to- 
gether by  lymphoid  tissue.  This  in  turn  is 
surrounded  by  a  layer  of  columnar  cells  and 
covered  by  the  mucous  coat  of  the  intestine. 
After  the  food  has  been  digested  it  passes  into 
the  lacteals  and  capillaries  of  the  villi,  so  that 
this  arrangement  increases  the  surface  for 
absorption. 

Glands  and  nodes  of  the  small  intestine. 
—  Besides  these  projections  formed  for  ab- 
sorption the  mucous  membrane  is  thickly 
studded  with  secretory  glands  and  nodes. 
These  are  known  as  — 

1.  Simple  follicles  or  crypts  of  Lieber- 
kuhn. 
2.  Duodenal  or  Brunner's  glands. 

[  (a)  Solitary  lymph  nodules. 
[  (h)  Aggregated  lymph  nodules. 
(1)  Simple  follicles.  —  These  glands  are  found  all    over    the 
surface  of  the  small  and  large  intestine.     They  are  simply  tubular 


Fig.  153. — An  Intes- 
tinal Villus,  a,  a,  a, 
columnar  epithelium ; 
b,  b,  capillary  network ; 
d,  lacteal  vessel. 


3.  Lymph  nodules 


268  ANATOMY  FOR  NURSES  [Chap.  XIV 

depressions  in  the  mucous  membrane,  lined  with  columnar  epithe- 


lium. 


(2)  Duodenal   glands.  —  These   glands   are   better   known   as 
Brunner's    jiiaiuls.     They   are    compound    glands   found   in   the 


Fig.  154.  —  Portion  of  the  Mucous  Membrane,  fro.m  the  Ileum.  Mod- 
erately magnifietl,  exhibiting  the  villi  on  its  free  surface,  and  between  them  the 
orifices  of  the  tubular  glands.  1,  portion  of  an  aggregated  lymph  nodule;  2,  a 
solitary  lymph  nodule  ;    3,  fibrous  tissue.     (Dalton.) 

submucous  tissue  of  the  duodenum.  The  simple  follicles  and  the 
duodenal  glands  secrete  the  intestinal  digestive  juice  which  is 
named  the  succus  entericus. 

(3)  Lymph  nodules.  —  The.se  are  of  two  varieties,  (a)  solitary 
lymph  nodules,  (b)  aggregated  lymph  nodules  of  Peyer. 


Fig.  155.  —  Mucosa  of  Small  Intestine  in  Ideal  Vertical  Cro88-8BCTion. 

(Gerrish.) 


Chap.  XIV]  THE  DIGESTIVE  SYSTEM  269 

(a)  Solitary  lymph  nodules.  —  Closely  connected  with  the  lym- 
phatic vessels  in  the  walls  of  the  intestines  are  small,  rounded 
bodies  of  the  size  of  a  small  pin's  head,  called  solitary  lymph 
nodules.  These  bodies  consist  of  a  rounded  mass  of  fine  lym- 
phoid tissue,  the  meshes  of  which  are  crowded  with  leucocytes. 
Into  this  mass  of  tissue  one  or  more  small  arteries  enter  and  form 
a  capillary  network,  from  which  the  blood  is  carried  away  by 
one  or  more  small  veins.  Surrounding  the  mass  are  lymph 
channels  which  are  continuous  with  the  lymphatic  vessels  in  the 
tissue  below. 

Aggregated  lymph  nodules.  —  They  are  simply  collections  of 
lymph  nodules,  commonly  called  Peyer's  patches.  A  well-formed 
Peyer's  patch  consists  of  fifty  or  more  of  these  solitary  lymph 
nodules,  arranged  in  a  single 
layer,  close  under  the  epithe- 
lium of  the  intestinal  mucous 
membrane,  and  stretching 
well  down  into  the  tissue  be- 
neath. These  patches  are 
circular  or  oval  in  shape, 
from  one-half  to  three  inches 
(12.5-75  mm.)  long,  and  one- 
half  inch  (12.5  mm.)  wide, 
and  from  twenty  to  thirty  in 

number        TheV    are    lartrest      ^^^-  156.  — -  Aggregated  Lymph  Nodule 

"^  .     ^  /■  (Peyer's  Patch).     (Gerrish.) 

and  most   numerous  in  the 

ileum.  They  increase  in  size  during  digestion.  These  Peyer's 
patches  are  the  seat  of  local  inflammation  and  ulceration  in 
typhoid  fever.  It  is  interesting  to  note  that  in  this  condition, 
the  long  axis  of  the  ulcer  runs  in  the  same  direction  as  the  long 
axis  of  the  intestine ;  whereas  in  tuberculosis  of  the  intestine, 
the  long  axis  of  the  ulcer  is  at  right  angles  to  the  long  axis  of  the 
intestines. 

Function.  —  It  is  in  the  small  intestine  that  the  greatest  amount 
of  digestion  and  absorption  takes  place.  The  valvulae  conniventes 
delay  the  food  so  that  it  is  more  thoroughly  subjected  to  the  action 
of  the  digestive  juices ;  and  being  covered  with  villi  they  increase 
the  surface  for  absorption.  The  glands  of  the  small  intestine 
secrete  the  succus  entericus  which  aids  in  the  digestion  of  food. 


270 


ANATOMY  FOR  NURSES 


[Chap.  XIV 


THE  LARGE  OR  THICK   INTESTINE 

The  largeness  of  the  next  division  of  the  alimentary  canal  is  in 
its  transverse,  not  in  its  longitudinal,  diameter ;  for  it  is  only  about 
five  feet  (1.5  m.)  long,  but  is  much  wider,  being  two  and  one-half 
inches  (63  mm.)  in  its  broadest  part.  It  extends  from  the  ileum 
to  the  anus.  Like  the  small  intestine,  it  is  divided  into  three  jjarts : 
the  caecum  with  the  vermiform  appendix,  colon,  and  rectum. 
The   caecum.  —  The   caecum    {cwcus,   blind)    is    a    large   blind 

pouch  at  the  commencement  of 
the  large  intestine.  The  small 
intestine  opens  into  the  side 
wall  of  the  large  intestine  about 
two  and  a  half  inches  ((53  mm.) 
above  its  —  the  large  intes- 
tine's —  commencement,  the 
ca.^cum  forming  a  cul-de-.sac  be- 
low the  opening.  The  opening 
from  the  ileum  into  the  large 
intestine  is  j^rovided  with  two 
large  projecting  lips  of  mucous 
membrane  which  allow  the  pas- 
sage of  material  into  the  large 
Fig.  1.57  -  Cavity  of  the  c^cdm,    jntestine,   but   etfcctuallv   pre- 

ITS  Front  \V  ALL  HAVING  BEEN  CUT  AWAY.  •     1     • 

The  valve  of  the  colon  and  the  opening  veut  the  paSSagC  of  material  111 
of  the  appendix  are  shown.      (Gerrish.)        ^^^    opposite    direction.      Thcse 

mucous  folds  form  what  is  known  as  the  valve  of  the  colon,  or  the 
ileo-cfecal  valve. 

The  vermiform  appendix  is  a  narrow,  wormlike  tube  about  the 
diameter  of  an  ordinary  lead  pencil,  and  from  three  to  seven 
inches  (7.5  to  17.5  cm.)  long.  It  is  attached  to  the  lower  end  of 
the  caecum,  but  its  directions  and  relations  are  very  variable.  In 
a  general  way  it  may  be  said  to  be  located  in  the  right  iliac  fossa. 

The  colon.  —  The  colon,  though  one  continuous  tube,  is  sub- 
divided into  the  ascending,  transverse,  and  descending  colon, 
with  the  sigmoid  flexure.  The  ascending  portion  ascends  on  the 
right  side  of  the  abdomen  until  it  reaches  the  under  surface  of  the 
liver,  where  it  bends  abruptly  to  the  left  (right  colic  or  hepatic 
flexure),  and  is  continued  across  the  abdomen  as  the  transverse 


Chap.  XIV]  THE  DIGESTIVE  SYSTEM  271 

colon  until,  reaching  the  left  side,  it  curves  beneath  the  lower 
end  of  the  spleen  (left  colic  or  splenic  flexure)  and  passes  downward 
as  the  descending  colon.  Reaching  the  left  iliac  region  on  a  level 
with  the  margin  of  the  crest  of  the  ileum,  it  makes  a  curve  like  the 
letter  S,  —  hence  its  name  of  sigmoid  flexure,  —  and  finally  ends 
in  the  rectum. 

The  rectum.  —  The  rectum  is  from  six  to  eight  inches  (15  to 
20  cm.)  long;  it  passes  obliquely  from  the  left  until  it  reaches 
the  middle  of  the  sacrum,  then  it  follows  the  curve  of  the  sacrum 
and  the  coccyx,  and  finally  arches  slightly  backward  to  its  ter- 
mination at  the  anus. 

The  anus  is  the  aperture  leading  from  the  rectum  to  the  exterior 
of  the  body.  It  is  guarded,  and  except  during  defecation  is  kept 
closed  by  the  contraction  of  two  involuntary  circvilar  muscles 
called,  respectively,  the  internal  and  external  sphincters. 

Coats  of  the  large  intestine.  —  The  large  intestine  has  the  usual 
four  coats  except  in  some  parts  where  the  serous  coat  only  par- 
tially covers  it,  and  the  rectum,  where  the  serous  coat  is  lacking. 
The  muscular  coat  consists  of  two  layers  of  fibres,  one  arranged 
longitudinally  and  the  other  circularly.  Beginning  at  the  appen- 
dix, the  longitudinal  fibres  are  arranged  in  three  ribbon-like  bands, 
which  extend  the  whole  length  of  the  colon  to  the  rectum,  and  these 
bands  being  shorter  than  the  rest  of  the  tube,  the  walls  are  puck- 
ered between  them.  The  third  coat  consists  of  submucous  areolar 
tissue,  and  the  fourth  or  inner  coat  consists  of  mucous  membrane. 
The  mucous  coat  possesses  no  villi  and  no  circular  folds.  It 
contains  numerous  tubular  glands  and  solitary  lymph  nodules 
which  closely  resemble  those  of  the  small  intestine. 

Functions.  —  The  functions  of  the  large  intestine  are  three. 

(1)  The  process  of  digestion  is  continued.  This  is  due  to  the  pres- 
ence of  bacteria,  and  to  the  digestive  juices  with  which  the  food 
became  mixed  in  the  small  intestine.  (2)  The  process  of  absorp- 
tion is  continued,  and  (3)  the  waste  products  are  removed  from  the 
body. 

ACCESSORY  ORGANS  OF  DIGESTION 

The  accessory  organs  of  digestion  are  :  (1)  the  salivary  glands, 

(2)  the  tongue,  (3)  the  teeth,  (4)  the  pancreas,  and  (5)  the  liver. 
The  first  three  have  been  described. 


272 


ANATOMY   FOR   NURSES  [Chap.  XIV 

PANCREAS 


The  pancreas  is  an  elongated  organ,  of  a  pinkish  color,  which 
lies  in  front  of  the  first  and  second  lumbar  vertebrae  and  behind 
the  stomach.  It  weighs  between  two  and  three  ounces  (60  to 
90  grams),  is  about  six  inches  (150  mm.)  long,  two  inches  (50 
mm.)  wide,  and  one-half  inch  (12.5  mm.)  thick.  In  shape  it 
somewhat  resembles  a  hammer,  and  is  divided  into  head,  body, 


HEPATIC  DUCT 


\^^^^^      ■/    '.^$  ,  SPLENIC  AR 


COMMON    BILE  DUCT 


ORIFICE  OF 

ACCESSORY 

PANCREATIC  DUCT 


FiQ.  158.  —  Ddcts  of  the  Pancreas.     Part  of  the  front  wall  of  the  duodenum 
is  cut  away.     (Gerrish.) 

and  tail.  The  right  end  or  head  is  thicker  and  fills  the  curve 
of  the  duodenum,  to  which  it  is  firmly  attached.  The  left,  free 
,end  is  the  tail,  and  reaches  to  the  spleen.  The  intervening  portion 
is  the  body. 

Structure  of  the  pancreas.  —  It  is  a  compound  secreting  gland 
and  consists  of  minute  tubes  coiled  up  into  little  masses  called 
lobules,  each  lobule  having  its  own  duct.  The  lobules  are  joined 
together  by  connective  tissue  to  form  lobes,  and  the  lobes,  united 
in  the  same  manner,  form  the  gland.  The  small  ducts  open  into 
one  main  duct  adbout  the  size  of  a  goose-quill,  which  runs  length- 


Chap.  XIV]  THE  DIGESTIVE  SYSTEM  273 

wise  through  the  gland,  from  the  tail  to  the  head.  The  pancreatic 
and  common  bile  duct  enter  by  means  of  a  common  opening  into 
the  duodenum  about  three  inches  (75  mm.)  beyond  the  pylorus. 

Islands  of  Langerhans.  —  Scattered  throughout  the  pancreas 
are  round  or  ovoid  bodies  known  as  the  islands  of  Langerhans. 
Each  island  is  about  one  twenty-fifth  inch  (1  mm.)  in  diameter 
and  consists  of  a  group  of  many-sided  cells.  They  are  surrounded 
by  a  rich  capillary  network.  Considerable  evidence  supports 
the  theory  that  the  internal  secretion  of  the  pancreas  is  formed 
by  these  islands. 

Function.  —  Two  secretions  are  formed  in  the  pancreas.  (1)  The 
pancreatic  juice,  which  is  one  of  the  most  important  of  the  diges- 
tive juices,  is  an  external  secretion  and  is  poured  into  the  duodenum 
during  intestinal  digestion.  (2)  The  secretion  formed  by  the 
islands  of  Langerhans  is  an  internal  secretion  that  is  absorbed  by 
the  blood  and  carried  to  the  tissues.  This  internal  secretion  aids 
in  the  oxidation  of  glucose. 

Diabetes  mellitus.  —  This  is  a  disease  characterized  by  a  lack 
of  oxidation  of  glucose  and  its  consequent  loss  to  the  body  as  it  is 
excreted  in  the  urine.  The  cause  is  not  settled,  but  it  is  believed 
that  disease  of  the  pancreas  involving  the  islands  of  Langerhans 
may  produce  this  condition. 

THE   LIVER 

The  liver  (hepar)  is  the  largest  gland  in  the  body,  weighing 
ordinarily  from  fifty  to  sixty  ounces  (1500  to  1800  grams). 
It  measures  ten  to  twelve  inches  (25  to  30  cm.)  from  side  to  side, 
six  to  seven  inches  (15  to  17.5  cm.)  from  front  to  back,  and  three 
to  four  inches  (7.5  to  10  cm.)  from  above  downward  in  its  thickest 
part.  It  is  a  dark  reddish  brown  organ,  placed  in  the  upper  right 
and  middle  portion  of  the  abdomen,^  and  extending  somewhat  into 
the  left  hypochondriac  region.  The  upper  convex  surface  fits 
closely  into  the  under  surface  of  the  diaphragm.  The  under  con- 
cave surface  of  the  organ  fits  over  the  right  kidney,  the  upper  por- 
tion of  the  ascending  colon,  and  the  p.vloric  end  of  the  stomach. 
The  number  five  prevails  in  the  parts  and  appendages  of  the  liver. 

Ligaments.  —  The  liver  is  held  in  place  by  five  ligaments,  four 
of  which  are  formed  by  folds  of  peritoneum,  and  the  fifth,  or  round 

1  Right  hypochondriac  and  epigastric  regions. 


274 


ANATOMY  FOR  NURSES  [Chap.  XIV 


Fig.  159.  —  The  Liver.     Front  View.     (Gerrish.) 

ligament,  results  from  the  atrophy  of  the  umbilical  vein  of  intra- 
uterine life. 

Fissures.  —  The  liver  is  divided  by  five  fissures  into  five  lobes. 
The  important  fissures  are  (1)  the  portal,  or  transverse,  which 
is  the  gateway  for  vessels,  ducts,  and  nerves  to  enter  and  leave 


Fig.  160.  —  The  Liver.     Lowlt  surface.      (Gerrish.) 


Chap.  XIV]  THE   DIGESTIVE  SYSTEM 


275 


the  liver,  and  (2)  the  gall  bladder  fissure,  which  supports  the  gall 
bladder.     Both  these  fissures  are  in  the  under  surface  of  the  liver. 
Lobes.  —  The  liver  is  divided  into  five  lobes :  — 

1.  Right  (largest  lobe). 

2.  Left  (smaller  and  wedge-shaped). 

3.  Quadrate  (square). 

4.  Caudate  (tail-like). 

5.  Spigelian. 

Vessels.  —  The  liver  has  five  sets  of  vessels :  — 

1.  Branches  of  portal  vein. 

2.  Hepatic  veins. 

3.  Bile  ducts. 

4.  Branches  of  hepatic  artery. 

5.  Lymphatics. 

Minute  anatomy  of  liver.  —  The  liver  may  be  regarded  as  made 
up  of  many  minute  livers  called  lobules.  Each  lobule  is  an  ir- 
regular body  about  one-twelfth  inch  (2  mm.)  in  diameter,  com- 
posed of  a  multitude  of  hepatic  cells  packed  so  closely  together 


Fig.  161.  —  Diagrammatic  Representation  of  two  Hepatic  Lobules. 
The  left-hand  lobule  is  represented  with  the  intralobular  vein  cut  across ;  in  the 
right-hand  one  the  section  takes  the  course  of  the  intralobular  vein,  p,  interlobular 
branches  of  the  portal  vein ;  /i,  intralobular  branches  of  the  hepatic  veins ;  s,  sub- 
lobular  vein.  The  arrows  indicate  the  direction  of  the  course  of  the  blood.  The 
liver-cells  are  only  represented  in  one  part  of  each  lobule. 

that  only  enough  room  is  left  between  them  for  the  passage  of 
vessels  and  nerves.  Thus  each  lobule  is  a  mass  of  hepatic  cells, 
pierced  everywhere  with  a  network  of  blood  capillaries. 


276 


ANATOMY   FOR  NURSES 


[Chap.  XIV 


Hepatic  cells.  —  Thev  are  about  i-q\s  of  an  inch  in  diameter, 
but  because  of  compression  are  very  irregular  in  shape.  They 
are  epitheHal  cells  composed  of  protoplasm,  with  a  single  clear 
nucleus,  but  no  cell-wall. 


Fio.  162.  —  Lobule  of  Rabbit's  Liver,  Vessels  and  Bile  Ducts  Injected. 
a,  central  or  intralobular  vein  ;  b,  b,  interlobular  veins  ;  c,  interlobular  bile  duct. 

The  portal  vein.  —  The  portal  vein,  after  entering  the  liver, 
divides  into  a  vast  number  of  branches  which  form  a  network 
surrounding  each  lobule,  and  hence  are  known  as  interlobular 
(between  the  lobules).  From  this  network  minute  capillaries 
enter  the  lobule,  penetrate  between  each  cell  and  thus  surround 
them,  so  that  each  cell  is  generously  supplied  with  blood  con- 
taining the  raw  material  for  the  manufacture  of  bile.  These 
capillary  branches  which  enter  the  lobule  and  surround  the  cells 


Chap.  XIV]  THE  DIGESTIVE   SYSTEM  277 

are  called  intralobular  (within  the  lobule).  These  vessels  con- 
verge toward  the  centre  of  the  lobule  like  the  spokes  of  a  wheel 
and  empty  into  a  vein  (intralobular)  which  carries  the  blood 
away  from  the  lobule.  The  intralobular  veins  from  a  number 
of  lobules  empty  into  a  much  larger  vein  upon  whose  surface  a 
vast  number  of  lobules  rest,  and  therefore  the  name  sublobular 
(under  the  lobule)  is  given  to  this  kind  of  veins.  They  empty 
into  still  larger  veins,  the  hepatic,  which  converge  to  a  few  large 
trunks  and  terminate  in  the  inferior  vena  cava,  which  is  em- 
bedded in  the  posterior  surface  of  the  gland. 

The  bile  ducts.  —  The  surfaces  of  the  hepatic  cells  are  grooved, 
and  the  grooves  on  two  adjacent  cells  fit  together  and  form  a 
channel  into  which  the  bile  is  poured  as  soon  as  it  is  formed  by 
the  cells.  These  channels  form  a  network  between  and  around 
the  cells  as  intricate  as  the  network  of  blood-vessels.  They  are 
called  intralobular  ducts,  and  empty  into  larger  ducts  called  in- 
terlobular. These  unite  and  form  larger  and  larger  ducts  until 
two  main  ducts,  one  from  the  right  and  one  from  the  left  side 
of  the  liver,  unite  in  the  portal  fissure  and  form  the  hepatic  duct. 

The  hepatic  duct  runs  downward  and  to  the  right  for  about 
two  inches  (50  mm.)  and  then  joins  at  an  acute  angle  the  duct 
from  the  gall-bladder,  termed  the  cystic  duct.  The  hepatic  and 
cystic  ducts  together  form  the  common  bile  duct  {ductus  com- 
munis choledochus) ,  which  runs  downward  for  about  three  inches 
(75  mm.)  and  enters  the  duodenum  about  three  inches  (75  mm.) 
below  the  pylorus.  This  orifice  serves  as  a  common  opening  for 
both  the  common  bile  and  the  pancreatic  duct.  It  is  very  small 
and  is  guarded  by  a  sphincter  muscle  which  keeps  it  closed  except 
during  digestion.     (See  Fig.  158.) 

Hepatic  artery.  —  We  must  remember  that  the  blood  brought 
to  the  liver  by  the  portal  vein  is  venous  blood  from  the  stomach, 
spleen,  pancreas,  and  intestines.  It  is  rich  with  the  products  of 
digestion  and  intended  for  the  manufacture  of  bile,  etc.  It 
is  not  intended  for  purposes  of  nourishment  of  the  liver  itself, 
hence  arterial  blood  is  furnished  by  the  hepatic  artery.  It  enters 
the  liver  with  the  portal  vein,  divides  and  subdivides  in  the  same 
way,  thus  forming  another  network  between  the  lobules,  and  in 
the  lobules  between  the  cells.  The  capillaries  from  the  portal 
vein  and  the  hepatic  artery  are  separate  and  distinct  until,  near 


278  ANATOMY  FOR  NURSES  [Chap.  XIV 

the  centre  of  each  lobule,  they  unite,  and  all  the  blood  sup])lied 
to  the  liver  is  carried  away  from  it  by  the  one  set  of  \eins  de- 
scribed under  head  of  portal  vein. 

Lymphatics.  —  There  is  a  deep  and  a  superficial  set.  They 
begin  in  irregular  spaces  in  the  lobules,  form  networks  around 
the  lobules,  and  run  always  from  the  centre  outward.  They  drain 
off  waste  j)roducts  and  unconsumed  nutritious  substances. 

Glisson's  capsule.  —  The  whole  liver  is  invested  in  an  outer 
capsule  of  areolar  connective  tissue,  which  is  reflected  inward 
at  the  portal  fissure  and  encloses  the  vessels  and  ducts  passing 
through  this  opening. 

Serous  membrane.  —  With  the  exception  of  a  few  small  areas, 
the  liver  is  enclosed  in  a  serous  tunic  derived  from  the  jjeritoneum. 

Nerves. — Nerves  are  derived  from  the  left  pneumogastric  and 
the  solar  plexus.^ 

Functions.  —  The  liver  may  be  compared  to  a  wonderful 
laboratory,  the  most  wonderful  in  the  body.  It  has  three  im- 
portant functions :  — 

1.  Bile  secreting.  —  The  cells  of  the  liver  manufacture  bile 
from  the  blood  brought  to  them  by  the  i)ortal  vein.  The  function 
of  bile  is  considered  in  the  next  chapter. 

2.  Glycogenic.  —  The  cells  of  the  liver  take  from  the  blood 
brought  to  them  by  the  portal  vein  a  substance  called  glucose, 
which  is  derived  from  the  carbohydrates  eaten.  This  is  stored 
in  the  liver  in  the  form  of  glycogen  until  such  time  as  the  body 
needs  more  glucose  than  the  food  eaten  furnishes.  When  such 
demand  is  made,  the  liver  cells  reconvert  the  glycogen  into  glucose 
and  pour  it  into  the  circulation, 

3.  Higher  chemical  actitities. — i\Iany  of  the  end  products  of  pro- 
tein digestion  are  toxic  substances.  Some  of  these  substances  are 
acted  upon  by  the  liver  and  rendered  less  harmful.  Others  are 
changed  into  urea,  and  in  the  form  of  urea  it  is  possible  for  the 
kidneys  to  eliminate  them  from  the  blood. 

The  gall-bladder.  — The  gall-bladder  is  a  pear-shaped  sac,  lodged 
in  the  gall-bladder  fissure  on  the  under  surface  of  the  liver,  where  it 
is  held  in  place  by  a  fold  of  the  peritoneum.  It  is  about  four  inches 
(10  cm.)  long,  one  inch  (25  mm.)  wide,  and  holds  about  ten  drachms 
(25  gms.).     It  is  composed  of  three  coats:  (1)  the  inner  one  is 

'  See  page  376. 


Chap.  XIV] 


SUMMARY 


279 


mucous  membrane,  (2)  the  middle  one  is  muscular  and  fibrous 
tissue,  and  (3)  the  outer  one  is  serous  membrane  derived  from 
the  peritoneum. 

Function.  —  The  gall-bladder  serves  as  a  reservoir  for  the  bile. 
During  digestion  the  bile  is  poured  steadily  into  the  intestine ; 
in  the  intervals  it  is  stored  in  the  gall-bladder. 

SUMMARY 

Digestion.  —  This  is  the  process  of  changing  food  into  products  ca- 
pable of  absorption.  It  is  dependent  on  the  proper  functioning  of 
certain  organs  that  are  grouped  together  and  called  the  digestive 
system. 

Mouth. 

Pharynx. 

(Esophagus,  or  gullet. 

Stomach. 


Digestive 
System 


Alimentary 
canal 


Small  or  thin  in^ 
testine 


( Duodenum. 
i  Jejunum. 
i  Ileum. 

f  Caecum. 

Large  or  thick  in-     ^  , 
^°  .  <  Colon 

testme  i  ^^  ,• 

-r,    j^         I  Descending. 
[  Rectum.  ° 


r  Ascending. 
<  Transverse. 


Accessory 
organs 


Alimentary 
Canal 


'  Salivary  glands. 
Tongue. 
Teeth. 
Pancreas. 
Liver. 
'  About  28  ft.  long. 
From  mouth  to  diaphragm  - 
3  coats 


From  diaphragm  to  rectum 
4  coats 


Above  — 
palate 


Hard  palate. 
Soft  palate  — 
tonsils. 


r  Mucous. 
<  Areolar. 
[  Muscular. 

Mucous. 

Areolar. 

Muscular. 

Serous  derived  from  peri- 
toneum. 


uvula,  palatine  arches,  and 


Mouth  or 
Buccal  Cavity 


Below  —  tongue. 
Front  —  lips. 
Sides  —  cheeks. 

Tonsils. 


Contains 


Tongue. 
Salivary  glands. 
I  Teeth. 


280 


ANATOMY  FOR  NURSES 


[Chap.  XIV 


Tonsils 


Tongue 


Salivary 
Glands 


Teeth 


Pharynx 


Function 


Collections  of  lymph  nodules  occupy  triangular  space 
between  palatine  arches  on  either  side  of  throat. 

1.  May  be  a  source  of  lymphocytes  and  leu- 
cocytes. 

2.  May  act  as  a  filter  and  prevent  entrance  of 
microorganisms. 

■  Special  organ  of  sense  of  taste. 

.     .  .       .     (I.  Stimulates  secretion  of  digestive  juices. 

Assists     m     „  .     .  ^    .  ...  °  ' 

,.       ,.      <  2.  Assists  in  swallowing, 

digestion     „  a        + 

I  3.  Secretes  mucus. 

Parotid  —  just  under  and  in  front  of  ear. 
Submaxil-    \ 

lary  >  Below  the  jaw  and  under  the  tongue. 

Sublingual  J 
Function  —  Form  a  secretion,  that  mixed  with  that  of  the 

mouth  is  called  saUva. 
Contained  in  sockets  of  alveolar  processes  of  maxillae  and 

mandible. 
Gums  —  cover  processes  and  extend  into  sockets. 
Sockets  —  lined  with  perios-  j  Attaches  teeth  to  sockets, 
teum  \  Source  of  nourishment. 

Root  —  one   or   more   fangs   contained   in 

socket. 
Crown  —  projects  beyond  level  of  gums. 
Neck  —  portion  between  root  and  crown. 
Gives  shape. 

Encloses  pulp  cavity  which  con- 
tains nerves  and  blood-vessels, 
that  enter  by  canal  from  root. 
Enamel  —  Caps  the  crown. 
Cement  —  Covers  the  root. 
1.  Temporary  —  r  Incisors  8 
7  months  to  <  Canines  4 
2i  yrs.  I  Molars  8 

Incisors  8 
Canines  4 
Premolars  8 
Molars  12 

Function  —  To  assist  in  the  process  of  mastication. 
Funnel-shaped  bag,  A^  inches  long,  between  mouth  and 

oesophagus. 
Muscular  and  lined  with  mucous  membrane. 

1  fauces. 

2  posterior  nares. 
2  Eustachian  tubes. 
1  larynx. 
1  oesophagus. 


3  portions 

Composed 
of  three 
substances 
developed 
from  epi- 
thelium 


2  sets 


Dentine  • 


2. 


Permanent — 6 
yrs.  to  21  yrs. 
of  age 


20. 


32. 


7  apertures " 


Chap.  XIV] 


SUMMARY 


281 


(Esophagus, 
or  Gullet 


3  coats 


Function — 


Stomach, 
Gaster 


or 


Curved 
upon 
itself 


Small  or  Thin 
Intestine 


f  Tube  —  9  in.  long.     Extends  from  pharynx  to  stomach. 
Inner  —  mucous  —  disposed  in  folds. 
Middle  —  submucous. 

r  Internal  circular  fibres. 
Outer  —  muscular  j  External     longitudinal 

I      fibres. 

1.  Connects  the  pharynx  with  the  stomach. 

2.  Receives  the  food  and  passes  it  on  to 
stomach. 

Hollow  pouch.     Capacity,  1  qt. 

Oblique  position  in  epigastric  and  left  hypochondriac 
regions. 

'Greater  curvature,  below,  directed  toward 

the  left. 
Lesser  curvature,  above,  directed  toward  the 
right. 

Fundus  or  cardiac  end  is  in  contact  with  spleen. 
Pyloric  extremity  under  the  liver. 

Intermediate  region,  between  fundus  and  pyloric  extremity. 
Outer  —  serous  —  peritoneum. 

r  1.  Longitudinal  fibres. 
Muscular  <  2.  Circular. 
I  3.  Oblique. 
Submucous  —  vascular. 

r  Rugae. 
Mucous  < 

f  S.ympathetic  system. 
I  Pneumogastric  nerve. 
Blood-vessels  from  coeliac  axis. 

1.  Connect  the  oesophagus  with  the  intestine. 

2.  To  hold  the  food  while  it  undergoes  gas- 
tric digestion. 

3.  To  secrete  mucus  and  gastric  juice. 
Convoluted  tube  extends  from  stomach  to  valve  of  colon. 

Twenty  feet  coiled  up  in  abdominal  cavity. 

(  Duodenum, 
divisions  <  Jej  unum. 
I  Ileum. 
1 .  Serous  from  peritoneum,  called  mesentery. 
J  Longitudinal  layer. 
\  Circular  layer. 
(  Blood-vessels. 


4  coats 


Nerves 


Function 


Glands 


Peptic  \  .  . 

Pyloric  l^^^^^^J^^^^- 


2.  Muscular 


4  coats 


3.  Submucous 


4.  Mucous 


<  Lymphatics. 

I  Nerves. 

f  Circular  folds. 

I  Villi  —  contain  lacteals. 


282 


ANATOMY   FOR  NURSES 


[Chap.  XIV 


Small  or  Thin 
Intestine 


Glands 
and  nodes 


Simple  follicles 
Duodenal  or 
Brunncr's 


Ljinph  nodules 


>  Secrete  intestinal  juice. 

Solitary. 

Aggregated  Ijinph  nod- 
ules of  Pej'cr  —  fifty 
or  more  solitary  lymph  • 
nodules  form  so-called 
patches  in  small  in- 
testine. 


Function 


{Digestion. 
Absorption. 
Secretion  of  succus  entericus. 


3  divisions 


Colon 


Large  orThick 
Intestine 


'  Largeness   in   its   transverse,    not    in    its   longitudinal, 
diameter. 
Length,  5  ft.;  width,  2|  in.  to  1^  in. 
Extends  from  ileum  to  anus. 

Caecum,  with  vermiform  appendix. 
'  Ascending. 
Transverse. 

Descending      with      sigmoid 
flexure. 
Rectum  —     f  Internal  sphincter, 
anus  1  External  sphincter. 

1 .  Serous,  except  in  some  parts  it  is  only  a 
partial  covering,  and  at  rectum  it  is 
wanting. 

Arranged  in  tluee 

Longitu-  "b^^^'^    -    ^^^ 

dinal       }      ^^^d«  *^^*  ^^- 
laycr  S^^  ^*  appen- 

dix, and  extend 

Circular      [      to  rectum, 
layer 

3.  Submucous, 
r  No  villi. 

No  circular  folds. 

4.  IMucous    I  (  Tubular  glands. 
Numerous  <  SoUtary     lymph 

I     nodules.    . 

„        .  I  Continuance  of  digestion  and  absorption 

Function         ^,.    •      .•         r       ^ 
Ehmination  of  waste. 


4  coats 


2.  Muscular. 


Chap.  XIV] 


SUMMARY 


283 


Pancreas 


Liver 


Hammer 
shape 

Size 


Structure 


Function 


In  front  of  first  and  second  lumbar  vertebrse,  behind 
stomach. 

r  Head  attached  to  duodenum. 
<  Body  in  front  of  vertebra. 
I  Tail  reaches  to  spleen. 
Six  inches  long. 
Two  inches  wide. 
One-half  inch  thick. 
Weight  —  two  to  three  ounces. 

Compound  gland  — coiled  tubes  form  lobules. 
Lobules  held  together  by  connective  tissue 

form  lobes. 
Lobes  form  gland. 

Duct  from  each  lobule  empties  into  pan- 
creatic duct. 

1.  Secretes  pancreatic  juice. 

2.  Forms  an  internal  secretion. 

Largest  gland  in  body. 

(  Right  hypochondriac. 
Location     <  Epigastric. 

I  Left  hj'pochondriac. 
Convex  above  —  fits  under  diaphragm. 
Concave  below  —  fits  over  right  kidney,  ascending  colon, 
and  pyloric  end  of  stomach. 
L  Suspensory, 
broad,        or 
falciform 
Five     liga-  I  2.  Coronary 
ments       |  3.  Right  lateral 

4.  Left  lateral 

5.  Round       liga- 
ment 

1.  Umbilical    fis- 
sure 

2.  Gall-bladder 
fissure 

3.  Portal  or  trans- 
verse fissure 

4.  Ductus  venous  i 
fissure  >  Dorsal  surface. 

5.  Vena  cava  J 

1.  Right  (largest  lobe). 

2.  Left  (smaller  and  wedge-shaped). 
Five  lobes  <!  3.  Quadrate  (square). 

4.  Caudate  (tail-like). 

5.  Spigelian. 


Five       fis 
sures 


Formed  by  folds  of  peri- 
toneum. 


Results  from  atrophy  of 
umbilical  vein. 


►  Under  surface. 


284 


ANATOMY   FOR  NURSES 


[Chap.  XIV 


Five 
sets  of 
vessels 


Liver 


Anatomy 
of  liver 


Functions 


Branches  of  por- 
tal vein 


Bile  ducts 


1.  Branches  of  portal  vein. 

2.  Bile  ducts. 

3.  Hepatic  veins. 

4.  Branches  of  hepatic  artery. 

5.  Lymphatics. 

Hepatic  cells  ttjVo  in.  in  diameter  grouped  in 

lobules. 
Lobules  h  in.  in  diameter. 

Interlobular  veins    (be- 
tween lobules). 
Intralobular    capillaries 

(within  lobules). 
Intralobular  veins 

(within  lobules). 
Sublobular  veins  (under 

lobules). 
Hepatic  veins  —  exit  at 
portalfissure,empty  in- 
to superior  vena  cava. 
Channels  between  cells 

(within  lobules). 
Intralobular  ducts. 
Interlobular  ducts. 
{  Hepatic  duct  —  exit  at 

portal  fissure. 
Interlobular  arteries  (be- 
tween lobules). 
Intralobular    capillaries 

(within  lobules). 
Course  bej^ond  the  in- 
tralobular   capillaries 
same  as  that  pursued 
by  blood  from  portal 
vein. 
Start   in   lobules,    form 
network,  and  run  from 
centre  to  periphery. 
Act  as  drain-pipes. 
Glisson's  capsule  encloses  the  whole  of  the 

liver. 
Serous  membrane  from  the  peritoneum  al- 
most completely  covers  it. 
L  Bile  secreting. 

2.  Glycogenic. 

„    TT-  u        u      •    f  Renders  waste  products 

3.  Higher  chemi-        ,  .  * 

,      ..  ...     <      less  toxic, 
cal  activities    _, 

I  Forms  urea. 


Branches    of    he- 
patic artery 


Lymphatics 


Chap.  XIV] 


SUMMARY 


285 


'  Pear-shaped  sac  lodged  in  gall-bladder  fissure  on  under 
surface  of  liver. 

r  Two  inches  long. 
Size  <  One  inch  wide. 

Gall-bladder  {  (  Capacity  about  ten  drachms. 

(  1.  Mucous  membrane. 
3  coats         I  2.  Fibrous  and  muscular  tissue. 

i  3.  Serous  membrane  from  peritoneum, 
,  Function  —  Serves  as  a  reservoir  for  bile. 


CHAPTER   XV 

CLASSIFICATION  OF  FOOD.  —  DIGESTIVE  PROCESSES;  CHANGES 
THE  FOOD  UNDERGOES  IN  THE  MOUTH,  STOMACH,  SMALL 
AND    LARGE    INTESTINE;    ABSORPTION 

Digestion.  —  The  process  of  digestion  takes  place  in  the  ali- 
mentary canal,  and  the  purpose  of  it,  as  stated  in  a  previous  chapter, 
is  to  change  the  food  that  we  eat  into  a  soluble  form,  so  that  it  can 
pass  through  the  intestinal  membranes  and  be  absorbed  by  the 
blood. 

Definition  of  food.  —  A  food  may  be  defined  as  a  substance  that 
contains  one  or  more  of  the  constituents  found  in  the  body,  or  a 
substance  which  the  tissues  of  the  body  can  act  upon  and  convert 
into  material  for  the  production  or  repair  of  living  tissue,  or  to 
yield  energy. 

CLASSIFICATION   OF  FOOD 

As  commonly  used  the  term  food  includes  everything  that  we 
eat  and  drink  and  comprises  a  great  variety  of  substances. 
Chemical  analysis  enables  us  to  divide  all  these  substances  into 
two  great  classes,  and  these  are  further  subdivided  as  follows :  — 

1.  Inorganic  I  ^'        .  . 

[  Alnierai  matter  or  salts. 

I"  Proteins. 

2.  Organic     <  Carbohydrates. 

[  Fats. 

Water.  —  Water  (HoO)  is  a  very  stable  compound  of  hydrogen 
and  oxygen.  It  does  not  yield  energy,  but  it  does  enter  into  the 
composition  of  all  the  tissues,  supplies  fluid  for  the  body,  acts  as 
a  solvent  for  food,  and  aids  in  the  elimination  of  waste.  Next 
to  air  it  is  the  most  necessary  principle  of  life  and  constitutes  about 
two-thirds  of  the  body  weight  (66  per  cent). 

286 


Chap.  XV]  CLASSIFICATION   OF  FOOD  287 

Salts.  —  The  principal  inorganic  salts  are  :  — 

Chloride 

Phosphate       »       ,.  ,       ,       . 

^  ,  ,  >  or  sodium  and  potassium, 

bulphate 

Carbonate 

Phosphate  1    p      ,  •  , 

_,    ,  >  or  calcium  and  magnesium. 

Carbonate  J 

The  inorganic  salts  are  not  oxidized  in  the  body  and  therefore 
do  not  yield  energy,  but  they  are  an  essential  part  of  all  the  tissues, 
and  take  part  in  the  functions  of  the  body  in  six  ways:  (1)  they 
maintain  the  alkaline  or  neutral  reaction  of  the  fluids  of  the  body ; 
(2)  they  furnish  the  material  for  the  acidity  or  alkalinity  of  the 
digestive  fluids  and  other  secretions ;  (3)  they  help  in  regulating 
the  flow  of  fluids  to  and  from  the  tissues,  because  they  maintain 
the  normal  osmotic  pressure ;  (4)  they  enter  largely  into  the 
composition  of  the  bones,  teeth,  and  cartilage ;  (5)  they  are 
necessary  for  the  clotting  of  blood ;  and  (6)  they  give  the  fluids 
of  the  body  their  influence  upon  the  elasticity  and  irritability  of 
nerve  and  muscle. 

Proteins.  —  Proteins  are  complex  compounds  and  consist  of 
carbon,  hydrogen,  nitrogen,  oxygen ;  sulphur,  phosphorus,  and 
other  elements  may  be  present.  They  differ  from  carbohydrates 
and  fats  in  having  nitrogen  and  therefore  are  described  as  nitroge- 
nous compounds.     They,  occur  in  the  form  of :  — 

Albumins.  —  Simple  proteins  that  are  soluble  in  water  and 
coagulable  by  heat.  The  white  of  egg  when  cooked,  the  scum 
that  forms  on  milk  when  it  is  heated,  and  the  coating  that  forms 
on  meat  when  it  has  been  subjected  to  high  temperature  are  all 
forms  of  albumin  that  have  been  coagulated  by  heat. 

Caseinogen.  —  If  milk  is  allowed  to  stand  until  it  sours,  or  if 
the  process  is  hastened  by  the  addition  of  acid  or  rennet,  the 
caseinogen  is  formed  into  a  curd. 

Gluten.  —  This  is  the  starchy  nitrogenous  substance  found  in 
wheat  flour. 

Legumin.  —  This  is  a  protein  substance  found  in  vegetables 
that  are  classed  as  legumes,  i.e.  peas,  beans,  lentils,  etc. 

Extractives.  —  These  are  protein  substances  found  in  plant 
and  animal  bodies  as  a  result  of  their  metabolism. 


288 


ANATOMY  FOR  NURSES 


[Chap.  XV 


Carbohydrates. — All  sugars  and  starches  are  grouped  together 
under  the  name  of  carbohydrates.  They  contain  but  three  ele- 
ments, carbon,  hydrogen,  and  oxygen,  the  two  latter  in  the  pro- 
portion to  form  water.  The  varieties  of  carbohydrates  are  as 
follows :  — 

Glucose  or  dextrose,   found   in   fruits,  es- 
pecially the    grape,    and  in    the    blood. 
CeHnOc 
Fructose   or   levulose,  found  with   glucose 
in  fruits.     C6H12O6.  J 

r  Sucrose  or  cane  sugar.  C12H22O11. 
<  Lactose  or  milk  sugar.  Ci2H220n. 
I  Maltose  or  malt  sugar.     C12H22OU. 


Simple  or  Mono 
saccharids 


Complex  or 
Disaccharids 


Invert 
sugai 


Sugars.  —  A  study  of  the  formulge  of  the  complex  sugars  will 
show  that  the  composition  is  the  same,  but  they  are  differently 
named  because  they  give  different  reactions.  Before  any  of 
the  complex  sugars  can  be  utilized  in  the  body  they  must  first 
be  changed  either  into  glucose,  or  into  invert  sugar,  which  consists 
of  a  molecule  each  of  glucose  and  fructose.  One  molecule  of  a 
complex  sugar  plus  one  molecule  of  water  will  form  one  mole- 
cule of  glucose  and  fructose. 

Complex  Sugar     Water  Glucose         Fructose 

0^1^22011    +  H2O  =    C6H12O6  .  C(>Hi20c 


Invert  Sugar. 


Polysaccharids     < 


Starch  —  found  in  grain,  tubers,  roots,  etc.     (CeHioOs)/^ 

Cellulose  —  outside  covering  of  starch 
grains,  and  basis  of  all 
woody  fibres.  (CeHioOs)?! 

Glycogen  —  form  in  which  sugar  is  stored 

in  liver.  (C6nio05)n 

Dextrin  —  fomicfl  from  starch  by  par- 
tial hydrolysis.  (CeHioOs)/! 


Polysaccharids.  —  In  all  of  these  compounds  the  composition 
of  the  molecule  is  supposed  to  be  rather  complex,  although  the 
elements  are  present  in  each  in  the  same  relative  proportion, 
as  shown  in  the  formulae.  The  value  of  n,  however,  may  be  very 
small  or  very  large  and  is  probably  different  for  each  polysaccha- 
rid,  which  makes  the  actual  composition  of  each  member  of  the 


Chap.  XV]  DIGESTIVE  PROCESSES  289 

group  different.  For  instance,  n  for  the  starch  molecule  is  large, 
while  for  the  dextrin  molecule  it  is  smaller,  so  that  a  single  starch 
molecule  in  digestion  may  split  into  several  molecules  of  dextrin 
of  the  same  relative  composition. 

Fats.  —  Fats  are  composed  of  carbon,  hydrogen,  and  oxygen,  but 
the  two  latter  elements,  hydrogen  and  oxygen,  are  not  in  the  pro- 
portion to  form  water.  They  are  not  simple  substances,  but  are 
mixtures  of  palmitin,  stearin,  and  olein,  which  are  derived  from  the 
fatty  acids  named  respectively  palmitic,  stearic,  and  oleic.  Each 
molecule  of  a  simple  fat  is  made  from  one  molecule  of  glycerine 
and  three  molecules  of  a  fatty  acid. 

Glycerine  Stearic  Acid  Stearin  Water 

C3H5(OH)3  +  3  H  .  C18H35O0  ->  C3H5(CisH3502)3  +  3  H2O. 

In  general,  fats  and  oils  are  practically  the  same,  and  the  mixture 
of  fats  found  in  the  body  is  liquid  at  the  body  temperature.  They 
are  soluble  in  ether,  chloroform,  and  hot  alcohol,  but  are  insolu- 
ble in  water. 

Decomposition  of  fats.  —  Under  the  influence  of  steam,  mineral 
acids,  and  certain  ferments  found  in  the  body,  fats  split  up  into  the 
substances  out  of  which  they  are  built,  i.e.  glycerine  and  fatty 
acid. 

Stearin  Water  Glycerine  Stearic  Acid 

C3H5(Ci8H3502)3    +  3  H2O ->  C3H5(OH)3    +  3  H  .  C18H35O2. 

The  process  of  saponification  is  similar  to  the  above,  only  that 
instead  of  water  a  base  is  used  and  the  final  products  are  glyce- 
rine and  soap. 

Stearin  Potassium  Hydroxide      Glycerine  Soap 

C3H5(Ci8H3502)3    +  3  KOH  -^  C3H5(OH)3    +  3  K(Ci8H3502). 

Necessity  for  digestion.  —  Digestion  is  necessary  because 
organic  foods,  with  the  exception  of  simple  sugars,  are  not  soluble 
in  water,  hence  they  cannot  be  absorbed.  Inorganic  foods  are 
absorbed  directly,  because  salts  dissolve  in  water. 

DIGESTIVE  PROCESSES 

Digestion  consists  of  two  processes,  i.e.  mechanical  and  chemical. 

Mechanical  processes.  —  Mechanical  processes  consist  of  vari- 
ous movements  that  result  from  the  action  of  the  muscles  in  the 
alimentary  canal.     They  serve  two  important  purposes:    (1)  in 


290  ANATOMY  FOR  NURSES  [Chap.  XV 

taking  food  in  and  moving  it  along  through  the  digestive  canal, 
and  (2)  in  separating  the  food  into  small  particles  upon  which 
the  digestive  fluids  can  act  rapidly.     These  processes  consist  of :  — 

1.  Mastication. 

2.  Deglutition. 

3.  Peristaltic  action  of  oesophagus. 

4.  Peristaltic  action  of  stomach. 

5.  ^Movements  of  the  intestines. 

6.  Defecation. 

Chemical  digestion.  —  Chemical  digestion  is  a  process  of  hy- 
drolysis which  is  dependent  upon  the  presence  of  enzymes.  By  the 
term  hydrolysis  is  meant  the  breaking  down  of  complex  molecules 
into  simpler  ones  with  the  absorption  of  water.  An  example  of 
hydrolysis  is  the  conversion  of  any  of  the  complex  sugars  into 
simpler  sugars.  (See  page  8.)  In  the  disaccharids  only  one 
splitting  is  necessary,  as  each  molecule  of  a  complex  sugar  plus  one 
molecule  of  water  will  give  two  molecules  of  a  simple  sugar  which 
is  soluble  and  read>'  for  absorption.  The  starches  are  more  com- 
plex in  their  composition,  hence  they  must  pass  through  several 
stages  of  decomposition  before  they  are  changed  by  hydrolysis 
to  a  simple  sugar.  Each  splitting  of  the  molecule  gives  substances 
with  simpler  composition,  though  with  the  same  relative  proportion 
of  the  constituents,  and  to  each  such  substance  produced  is  given 
a  special  name.  The  proteins  are  even  more  complex  than  the 
starches,  and  pass  through  a  greater  number  of  stages  in  the 
process  of  digestion.  The  substances  formed  in  each  stage  are  of 
lighter  molecular  weight  and  are  named  (1)  meta-proteins,  (2)  pro- 
teoses, (3)  peptones,  (4)  polypeptids,  and  (5)  amino-acids. 
Many  physiologists  are  of  the  opinion  that  protein  digestion  does 
not  pass  beyond  the  peptone  stage,  as  peptones  are  soluble  and 
can  be  absorbed. 

Fats  are  hydrolyzed and  split  up  into  fatty  acids  and  glycerine; 
the  fatty  acids  are  then  acted  upon  by  the  bile  and  pancreatic 
juice,  and  form  soap.     (See  page  298.) 

Cause  of  chemical  digestion.  —  It  is  possible  to  make  carbo- 
hydrates, proteins,  and  fats  undergo  the  same  changes  outside 
the  body  as  occur  during  digestion.  Carbohydrates,  proteins, 
and  fats,  if  boiled  with  a  mineral  acid  or  subjected  to  the  action 
of  enzA'mes,  will  hydrolyze  and  split  up  into  simpler  substances. 


Chap.  XV]  DIGESTIVE   PROCESSES  291 

Within  the  body  the  change  takes  place  at  body  temperature, 
and  is  due  to  the  presence  of  organic  ferments  or  enzymes  present 
in  all  of  the  digestive  juices. 

Enzymes. — An  enzyme  is  an  organic  ferment  produced  by  living 
cells,  and  is  capable  of  effecting  chemical  change  without  itself 
undergoing  alterations  in  the  process.  Each  enzyme  has  a  definite 
action  at  a  suitable  temperature,  and  will  only  work  in  a  medium 
of  definite  reaction,  either  acid  or  alkaline.  Further,  the  products 
of  the  action  must  be  removed,  and  in  the  body  this  is  accomplished 
by  absorption. 

CHANGES  THE  FOOD   UNDERGOES  IN  THE  MOUTH 

Mastication.  —  \\Tien  solid  food  is  taken  into  the  mouth  it  is 
cut  and  ground  by  the  teeth,  being  pushed  between  them  again 
and  again  by  the  muscular  contractions  of  the  cheeks  and  the 
movements  of  the  tongue  until  the  whole  is  thoroughly  crushed 
and  ground  down. 

Insalivation.  —  During  the  process  of  mastication  saliva  is 
poured  in  large  quantities  into  the  mouth,  and  mixing  with  the 
food  moistens  it  and  reduces  it  to  a  soft,  pulpy  condition,  A  cer- 
tain amount  of  air  caught  in  the  bubbles  of  the  saliva  also  becomes 
entangled  in  the  food,  and  this  facilitates  the  penetration  of  the 
gastric  juice. 

Secretion  of  saliva.  —  The  secretion  of  saliva  is  the  result  of 
reflex  stimulation  of  the  nerves  connected  w^ith  the  salivary  glands. 
The  movements  of  mastication,  the  taste  and  odor  of  food,  act  as 
stimulants  to  the  sensory  or  afferent  nerves  which  carry  these  im- 
pulses to  a  nerve  centre  in  the  brain  (probably  in  the  medulla 
oblongata),  and  from  thence  motor  impulses  are  transmitted 
through  efferent  nerves  to  the  gland.  Psychical  acts  may  also 
influence  the  secretion  of  saliva,  as  for  example  the  thought  or 
smell  of  food,  or  a  feeling  of  nausea  may  stimulate  the  secretion, 
and  anger,  fear,  or  worry  may  inhibit  it. 

Saliva.  —  Saliva  is  a  mixture  of  the  secretions  of  all  three  pairs 
of  salivary  glands,  as  well  as  of  the  small  glands  of  the  mucous 
membrane  of  the  mouth.  It  consists  of  water,  some  mucus, 
and  an  enzyme  called  ptyalin.  It  has  a  specific  gravity  of  1.004 
to  1.008  and  an  alkaline  reaction.  The  amount  secreted  in  twenty- 
four  hours  is  estimated  to  be  from  one  to  two  quarts. 


292  ANATOMY   FOR   NURSES  [Chap.  XV 

The  functions  of  saliva.  —  Saliva  has  four  distinct  functions. 
(1)  It  assists  in  speech  by  moistening  the  mucous  membrane  of 
the  mouth  and  tongue.  (2)  It  assists  in  mastication  and  degkiti- 
tion  by  softening  and  moistening  the  food.  SaHva  causes  the 
masticated  portions  to  stick  together  and  thus  helps  to  form  a 
bolus  which  is  coated  with  mucus  and  easily  swallowed. 

(3)  It  renders  soluble  substances  capable  of  being  tasted.  Salts, 
sugar,  acids,  and  bitters  are  dissolved  in  the  saliva. 

(4)  It  acts  upon  starch. 

Ptyalin.  —  By  the  ptyalin-ferment  present  in  saliva,  starch, 
which  is  an  insoluble  substance,  is  partially  changed  to  dextrin 
and  sugar  (maltose).  This  process  is  a  complicated  one  and  it  is 
probable  that  a  number  of  intermediate  compounds  exist  between 
the  huge  starch  molecule  and  the  dextrin  and  maltose.  This 
change  is  best  effected  at  the  temperature  of  the  body,^  in  a  slightly 
alkaline  solution,  saliva  that  is  distinctly  acid  hindering  or  ar- 
resting the  process.  Boiled  starch  is  changed  more  rapidly  and 
completely  than  raw,  but  the  food  is  never  retained  in  the  mouth 
long  enough  for  the  saliva  to  more  than  begin  the  transformation 
of  starchy  matters.- 

Deglutition,  or  swallowing.  —  The  food  thus  softened  and  moist- 
ened is  collected  from  every  part  of  the  mouth  by  the  movements 
of  the  tongue,  brought  together  upon  its  upper  surface,  and  then 
pressed  backward  through  the  fauces  into  the  pharynx.  The 
elevation  of  the  soft  palate  prevents  the  entrance  of  food  into  the 
nasal  chambers,  while  the  epiglottis  bars  its  entrance  into  the 
air-passages,  and  it  is  guided  safely  and  rapidly  through  the 
pharynx  into  the  oesophagus.  Here  it  passes  beyond  the  control 
of  the  will ;  it  is  grasped  by  the  oesophageal  muscles  and  by  a 
continuous  peristaltic  action  is  carried  downward.  The  cardiac 
orifice  of  the  stomach  is  guarded  by  a  sphincter  muscle  which  is 
normally  in  a  state  of  contraction.  The  peristaltic  wave  which 
passes  slowly  down  the  oesophagus  inhibits  this  contraction  and 
forces  the  food  into  the  stomach. 

During  the  process  of  mastication,  insalivation,  and  deglutition 
the  food  is  first   reduced   to  a  soft,   pulpy  condition ;    second, 

1  A  temperature  of  100°  F.  in  the  alimentary  canal  is  necessary  for  digestion, 
hence  iced  drinks  or  iced  foods  that  lower  this  temperature  delay  digestion, 

*  The  salivary  glands  do  not  become  active  until  the  subject  is  from  four  to  six 
months  old ;    hence  the  reason  for  avoiding  starchy  food  for  young  infants. 


Chap.  XV]  DIGESTIVE   PROCESSES  293 

any  starch  it  may  contain  begins  to  be  changed  into  sugar ;  third, 
it  acquires  a  more  or  less  alkaline  reaction. 

Vomiting.  —  Under  ordinary  circumstances  the  contractions  of 
the  cardiac  sphincter  muscle  prevent  the  regurgitation  of  food,  but 
strong  contractions  of  the  stomach  or  spasmodic  contractions  of 
the  abdominal  muscles  may,  if  the  diaphragm  is  fixed,  force  the 
contents  of  the  stomach  through  the  oesophagus  and  mouth  to  the 
exterior.     This  is  called  vomiting., 

CHANGES  THE  FOOD  UNDERGOES  IN  THE  STOMACH,  OR 
STOMACH  DIGESTION 

Peristaltic  action  of  the  stomach.  —  The  food  which  enters  the 
stomach  is  delayed  there  by  the  contraction  of  the  sphincter  muscles 
at  the  cardiac  and  pyloric  openings.  The  cavity  of  the  stomach  is 
always  the  size  of  its  contents,  which  means  that  when  it  is  empty 
it  is  contracted,  but  when  food  enters  it  expands  just  enough  to 
hold  it.  Within  a  few  minutes  after  the  entrance  of  food  small 
contractions  start  in  the  middle  region  of  the  stomach  and  run 
toward  the  pylorus.  These  contractions  are  regular  and  become 
more  and  more  forcible  as  digestion  progresses.  As  a  result  of 
these  movements  the  food  is  macerated,  mixed  with  the  acid  gastric 
juice,  and  reduced  to  a  liquid  mass  called  chyme.  At  intervals  the 
pyloric  sphincter  relaxes  and  the  wave  of  contraction  forces  some 
of  the  chyme  into  the  duodenum.  The  fundal  end  of  the  stomach 
does  not  take  part  in  these  movements,  but  serves  as  a  reservoir 
for  food  which  is  under  slight  pressure,  as  the  muscles  are  in  a  state 
of  continual  contraction  or  tone.  Due  to  the  lack  of  movement 
and  the  muscular  tone,  the  gastric  juice  cannot  penetrate  the  bolus 
of  food,  and  the  ptyalin  with  which  it  became  mixed  in  the  mouth 
continues  its  action,  and  the  digestion  of  starch  continues  for  about 
twenty  minutes.  As  the  chyme  is  gradually  forced  into  the  duode- 
num, the  pressure  of  the  fundus  forces  the  food  into  the  pyloric 
end. 

Time  required  for  stomach  digestion.  —  It  is  obvious  that  the 
time  required  for  gastric  digestion  depends  upon  the  nature  of  the 
food  eaten.  An  average  meal  of  mixed  food  requires  about  five 
hours  for  gastric  digestion.  The  ejection  of  chyme  through  the 
pylorus  occurs  at  regular  intervals,  and  is  supposed  to  depend 
upon  the  consistency  and  acidity  of  the  chyme.     Solid  particles 


2<)4  ANATOMY   FOR   NURSES  [Chap.  XV 

forced  against  the  pylorus  tend  to  keep  it  closed,  but  hydrochloric 
acid  in  the  stomach  seems  to  favor  or  produce  relaxation  of  the 
pyloric  sphincter.  In  the  intestines  hydrochloric  acid  has  a  con- 
trary effect,  as  it  causes  a  contraction  of  the  sphincter,  which 
remains  closed  after  each  ejection  until  the  acidity  has  been 
neutralized. 

Secretion  of  gastric  juice.  —  During  the  intervals  of  digestion 
the  stomach  is  bathed  in  an  alkaline  mucus.  The  entrance  of 
food  acts  as  a  stimulant  to  the  whole  organ.  The  blood-vessels 
dilate,  and  the  glands  pour  out  an  abundant  secretion  upon  the 
mucous  lining.  This  secretion  continues  as  long  as  food  remains 
in  the  stomach,  and  is  caused  and  maintained  by  two  factors : 
(1)  psychical,  the  sensations  of  eating,  the  taste  and  odor  of  food 
stimulate  the  sensory  nerves  situated  in  the  mouth  and  nose. 
These  afferent  impulses  are  transferred  through  nerve  centres 
to  efferent  fibres  of  the  pneumogastric  nerve,  and  thus  are  carried 
to  the  stomach.  (2)  Chemical,  (a)  by  secretogogues  contained  in 
certain  foods  and  (b)  by  secretogogues  contained  in  the  products 
of  digestion.  Certain  foods,  such  as  meat  juices  and  extracts,  con- 
tain substances  called  secretogogues  or  hormones  which  are  sup- 
posed to  act  directly  upon  the  nerves  of  the  pyloric  mucous 
membrane  and  form  a  substance  called  gastrin  or  gastric  secretin, 
which  is  absorbed  into  the  blood  and  carried  to  the  gastric  glands. 
This  substance  stimulates  the  glands  to  secretion.  Other  foods, 
such  as  milk,  bread,  white  of  egg,  etc.,  do  not  appear  to  contain 
secretogogues.  When  such  foods  are  eaten,  a  psychical  secretion 
is  started  and  when  this  has  acted,  some  products  of  their  digestion 
in  turn  become  capable  of  stimulating  a  further  secretion  of  gastric 
juice. 

Gastric  juice.  —  Gastric  juice,  -secreted  by  the  peptic  and 
pyloric  glands  in  the  mucous  lining  of  the  stomach,  is  a  thin, 
colorless,  or  pale  yellow  fluid,  of  an  acid  reaction.  The  amount 
secreted  in  twenty-four  hours  has  never  been  accurately  measured, 
but  has  been  estimated  to  be  about  fifteen  pints  (7.1  litres).  It 
contains  few  solids,  and  is  dependent  for  its  specific  action  upon 
two  enz^'mes  called  (1)  pepsin  and  (2)  rennin.  Pepsin  is  only 
properly  active  in  an  acid  solution,  and  we  therefore  find  that  free 
hydrochloric  acid  in  the  proportion  of  0.2  to  0.4  per  cent  is  always 
present  in  normal  gastric  juice. 


Chap.  XV]  DIGESTIVE   PROCESSES  295' 

The  action  of  gastric  juice  upon  food.  —  The  action  of  gastric 
juice  upon  food  is  dependent  on  (1)  hydrochloric  acid,  (2)  pepsin, 
and  (3)  rennin. 

(1)  Hydrochloric  acid. — The  hydrochloric  acid  found  in  the 
gastric  juice  is  supposed  to  be  secreted  by  special  cells  in  the  in- 
termediate portion  of  the  stomach,  from  chlorides  found  in  the 
blood.  The  chief  chloride  is  sodium  chloride  (NaCl),  and  by  some 
means  this  is  decomposed ;  the  chlorine  (CI)  combines  with  hydro- 
gen (H),  and  is  then  secreted  upon  the  free  surface  of  the  stomach 
as  hydrochloric  acid  (HCl).  Besides  giving  an  acid  medium, 
which  is  necessary  for  the  pepsin  to  carry  on  its  work,  it  serves : 
(1)  to  swell  the  protein  fibres  and  thus  give  easier  access  to  pep- 
sin, (2)  it  helps  in  the  inversion  of  sugar,  i.e.  changing  complex 
sugars  to  simple  ones,  (3)  it  acts  as  a  disinfectant  and  kills  many 
bacteria  that  enter  the  stomach,  and  (4)  it  helps  to  regulate  the 
opening  and  closing  of  the  pyloric  valve. 

(2)  Pejysin.  —  The  property  of  converting  proteins  into  peptones 
is  dependent  upon  the  enzyme  pepsin.  Whatever  the  protein 
may  be,  whether  the  albumin  of  eggs,  the  gluten  of  flour  in  bread, 
the  myosin  in  flesh,  the  result  is  the  same ;  pepsin,  in  conjunc- 
tion with  an  acid  at  the  temperature  of  the  body,  transforms  them 
into  peptones.  This  process  of  converting  an  insoluble  protein 
to  a  soluble  peptone  is  complicated,  as  the  protein  under  digestion 
passes  through  a  number  of  intermediate  stages.  Peptones 
readily  dissolve  in  water,  and  pass  with  ease  through  animal 
membranes. 

(3)  Rennin.  —  So  far  as  is  known,  this  ferment  acts  only  upon 
the  soluble  protein  of  milk,  which  is  called  caseinogen.  It  converts 
this  substance  into  a  clotted  mass  called  curd,  which  is  later 
prepared  for  absorption  by  the  action  of  the  enzyme  pepsin. 

The  gastric  juice  has  no  action  upon  starch,  and  upon  fats  it  has 
at  most  a  limited  action.  The  fats  are  set  free  from  their  mixture 
with  other  food-stuffs  by  the  dissolving  action  of  the  gastric  juice, 
they  are  liquefied  by  the  heat  of  the  body,  and  are  scattered 
through  the  chyme  in  a  coarse  emulsion  by  the  movements  of  the 
stomach.  In  addition  to  pepsin  and  rennin,  various  authorities 
describe  other  enzymes  in  the  gastric  juice,  but  there  is  a  good  deal 
of  uncertainty  regarding  them.  It  is  probable  that  a  third  enzyme, 
called  gastric  lipase,  acts  upon  fats  that  are  ingested  in  an  emulsi- 


296  ANATOMY   FOR   NURSES  [Chap.  XV 

fied  form,  and  this  action  may  be  important  in  the  digestion  of  milk 
fat  by  infants,  as  the  pancreas  is  inactive. 

CHANGES  THE  FOOD  UNDERGOES  IN  THE  SMALL 
INTESTINE 

The  ch^ine,  on  entering  the  duodenum,  after  an  ordinary  meal, 
is  a  mixture  of  various  matters.  It  contains  some  undigested 
proteins ;  some  undigested  starch  ;  oils  from  fats  eaten  ;  peptones 
formed  in  the  stomach  ;  salines  and  sugars  ;  all  mixed  with  a  good 
deal  of  water  and  the  secretions  of  the  alimentary  canal.  It  is  in 
the  intestines  that  this  mixture  undergoes  the  most  profound  diges- 
tive changes.  These  changes  which  constitute  intestinal  digestion 
are  effected  by  :  (1)  the  movements  of  the  intestines,  (2)  the  pan- 
creatic juice,  (3)  the  succus  entericus  or  secretion  of  the  intestinal 
glands,  and  (4)  the  bile. 

Movements  of  the  small  intestine.  —  The  movements  of  the 
small  intestine  are  of  two  kinds  :  (1)  peristaltic  and  (2)  rhythmic 
segmentation, 

(1)  A  peristaltic  movement  may  be  defined  as  a  quick  succession 
of  waves  of  contraction  and  inhibition  passing  slowly  along  the 
intestine  and  affecting  the  longitudinal  fibres.  The  wave  of 
contraction  begins  at  a  certain  point,  passes  downward  away  from 
the  stomach,  and  is  always  preceded  by  an  area  of  inhibition  or 
relaxation.  The  purpose  of  it  is  to  pass  the  food  slowly  forward, 
and  it  is  obvious  that  the  wave  of  contraction  is  more  effective  in 
forcing  the  contents  forward  because  just  in  front  of  it  the  intes- 
tine is  relaxed. 

(2)  The  movements  of  rhythmic  segmentation  consist  of 
contractions  of  the  circular  fibres  of  the  intestine,  which  occur  at 
the  same  time  as  the  contractions  of  the  longitudinal  fibres.  The 
purpose  of  these  contractions  is  to  split  the  column  of  food  into  a 
number  of  equal  segments.  Within  a  few  seconds  each  of  these 
segments  is  halved  and  the  corresponding  halves  of  adjoining 
segments  unite.  Again  contractions  recur  and  these  newly  formed 
segments  are  divided,  and  the  halves  re-form  in  the  same  position 
as  they  had  at  first.  In  this  way  every  particle  of  food  is  brought 
into  intimate  contact  with  the  vahiilre  conniventes  and  is 
thoroughly  mixed  with  the  digestive  juices. 

Secretion  of  pancreatic  juice.  —  Just  as  chewing  and  swallowing 


Chap.  XV]  DIGESTIVE   PROCESSES  297 

of  food  starts  the  gastric  secretion,  so  the  presence  of  acid  chyme  in 
the  intestine  starts  the  pancreatic  secretion.  This  effect  is  due  to 
a  special  substance  called  secretin  which  is  formed  by  the  action 
of  the  acid  upon  some  substance  present  in  the  mucous  membrane 
of  the  intestine.  This  secretin  is  absorbed  by  the  blood  and  carried 
to  the  pancreas,  which  it  stimulates  to  activity.  Like  the  secretin 
of  the  gastric  juice,  this  is  not  an  enzyme  but  a  hormone. 

Pancreatic  juice.  —  Healthy  pancreatic  juice  is  a  clear,  some- 
what viscid  fluid,  with  a  very  decided  alkaline  reaction.  The 
amount  secreted  in  twenty-four  hours  is  about  15  to  25  ounces 
(7.1  to  11  litres).  It  contains  few  solids  and  is  dependent  for  its 
remarkable  power  on  three  enzymes :  (1)  trypsin,  (2)  diastase 
(amylopsin),  and  (3)  lipase  (steapsin). 

Action  of  pancreatic  juice  upon  food.  —  Pancreatic  juice  has 
the  power  of  acting  on  all  the  food-stuffs,  proteins,  carbohydrates, 
and  fats.     This  action  is  due  to  its  enzymes. 

(1)  Trypsin.  —  Tr^^Dsin,  like  pepsin,  has  the  power  to  decompose 
proteins,  but  the  action  is  more  rapid  and  more  powerful,  and  the 
protein  molecule  is  broken  up  into  simpler  substances  than  pep- 
tones, depending  on  the  amount  of  trypsin  and  the  time  that  it  acts. 
If  complete  hydrolysis  takes  place,  the  end  products  consist 
chiefly  of  amino-acids.  Unlike  pepsin,  trypsin  requires  a  neutral  or 
alkaline  medium.  The  preliminary  action  of  pepsin,  on  a  protein 
molecule,  hastens  the  action  of  trypsin,  and  renders  it  more  com- 
plete than  if  the  trypsin  acted  alone. 

Diastase  {Amylopsin).  —  The  action  of  diastase  is  similar  to 
that  of  ptyalin.  It  causes  hydrolysis  of  starch  with  the  produc- 
tion of  maltose.  The  starchy  food  that  escapes  digestion  in  the 
mouth  and  stomach  becomes  mixed  with  this  enzyme  and  con- 
tinues under  its  action  until  the  ileo-caecal  valve  is  reached. 

Lipase  (Steapsin). — Lipase  is  an  enzyme  capable  of  decom- 
posing fats.     This  action  is  twofold  : 

(a)  It  emulsifies  them. 

(6)  It  splits  them  up  into  fatty  acids  and  glycerine. 

(a)  If  we  shake  up  olive  oil  with  water,  the  two  cannot  be  got 
to  mix :  as  soon  as  the  shaking  ceases,  the  oil  floats  to  the  top ; 
but  if  we  shake  up  olive  oil  with  pancreatic  juice,  the  oil  remains 
evenly  suspended  in  it.  The  reason  of  this  is  that  the  oil  has  been 
minutely  divided  into  tiny  droplets,  and  each  droplet  surrounded 


298  ANATOMY  FOR  NURSES  [Chap.  XV 

by  a  delicate  envelope  supplied  from  the  albumin  in  the  pancreatic 
juice,  so  that  they  cannot  fuse  together  to  form  the  large  drops, 
which  would  soon  float  to  the  top.^ 

(b)  The  fats  that  are  not  emulsified  are  broken  up  into  glycerine 
and  fatty  acids.  The  glycerine  is  absorbed,  and  the  fatty  acids 
in  the  presence  of  an  alkali  form  soaps  which  are  soluble  in  water 
and  capable  of  absorption.  It  is  probable  that  the  greater  part 
of  the  fat  is  absorbed  by  the  latter  method. 

Succus  entericus,  or  intestinal  juice.  —  Succus  entericus  is 
the  secretion  of  the  intestinal  glands.  It  is  a  clear,  yellowish 
fluid,  having  a  marked  alkaline  reaction  and  containing  a  certain 
quantity  of  mucus. 

The  number  of  enzymes  ^  described  as  present  in  succus  enteri- 
cus differs  with  different  authorities  audit  is  probable  that  the  entire 
physiology  is  not  known.  Its  chief  function  seems  to  be  a  continu- 
ation of  the  work  of  pepsin  and  trypsin  and  the  inversion  of  com- 
plex sugars  to  simple  ones.  It  also  acts  as  a  diluent  and  supplies  a 
loss  of  fluid. 

Bile.  —  Bile,  secreted  in  the  lobules  of  the  liver  and  stored  in 
the  gall-bladder  until  needed,  is  a  fluid  of  a  golden  brown  or 
greenish  color ^  with  an  alkaline  reaction.  The  quantity  secreted 
in  twenty-four  hours  varies  with  the  amount  of  food  taken,  but 
is  estimated  at  about  one  quart. 

Bile  contains  no  enzyme,  but  the  fact  that  it  is  poured  into  the 
intestine  through  an  orifice  common  to  it  and  the  pancreatic 
juice  suggests  that  these  two  fluids  cooperate  in  their  action  on 
food. 

Action  of  bile.  —  Its  most  important  function  as  a  digestive  is 
noted  in  its  action  on  fats. 

(1)  It  splits  up  neutral  fats  and,  assisted  by  the  pancreatic 
juice,  emulsifies  and  saponifies  them. 

(2)  It  aids  in  the  absorption  of  fats.  The  passage  of  digested 
food  through  membranes  is  assisted  by  wetting  the  membranes 
with  bile  or  with  a  solution  of  bile  salts.     It  is  known  that  oil 

1  This  fine  subdivision  of  fats  gives  the  white  color  to  the  chyle,  which  is'  its 
most  striking  external  characteristic,  the  innumerable  tiny  oil  drops  reflecting  all 
the  light  that  falls  on  its  surface. 

2  See  Summary  at  end  of  this  chapter. 

^  The  color  of  bile  is  determined  by  the  respective  amounts  of  the  bile  pigments : 
(1)  biliverdin,  and  (2)  bilirubin,  that  are  present. 


Chap.  XV]  DIGESTIVE  PROCESSES  299 

will  pass  to  a  certain  extent  through  a  filter  paper,  kept  wet  with 
a  solution  of  bile  salts,  whereas  it  will  not  pass,  or  passes  with 
extreme  difficulty,  through  one  kept  wet  with  distilled  water. 

(3)  It  has  a  feeble  and  questioned  antiseptic  action  upon  the 
intestinal  contents,  and  its  presence  limits  putrefaction  to  some 
extent. 

.  (4)  In  addition  to  being  a  secretion,  about  one-sixteenth  of  the 
bile  is  an  excretion,  as  it  furnishes  the  channel  by  which  the  products 
of  the  disintegration  of  haemoglobin  are  carried  from  the  body. 
(5)  It  acts  as  a  mild  laxative  by  stimulating  peristalsis.^ 
Action  of  bacteria  in  small  intestine.  —  Bacteria  are  constantly 
present  in  the  small  intestine,  but  only  those  capable  of  fermenting 
carbohydrate  food  show  any  activity.  If  the  products  of  protein 
digestion  are  promptly  absorbed,  there  is  no  fermentation  of  protein 
material.  Various  theories  are  offered  to  explain  this  protection 
of  protein,  but  opinions  differ,  even  among  investigators. 

CHANGES  THE  FOOD  UNDERGOES  IN  THE  LARGE 
INTESTINE 

Movements  of  the  large  intestine.  —  After  the  food  passes  from 
the  small  intestine  into  the  large  intestine,  its  regurgitation  is  pre- 
vented by  the  closure  of  the  ileo-csecal  valve.  When  the  caecum 
becomes  filled,  strong  contractions  of  the  walls  exert  pressure  upon 
the  contained  food  and  force  it  into  the  ascending  colon.  The 
waves  of  contraction  which  pass  over  the  walls  of  the  ascending 
colon  are  described  as  antiperistaltic  because  they  pass  in  two 
directions,  (1)  from  the  small  intestine,  and  (2)  toward  the  small 
intestine.  This  delays  the  food,  keeps  it  moving  backward  and 
forward,  and  helps  absorption.  It  has  been  estimated  that  it 
requires  about  two  hours  for  the  food  to  pass  from  the  ileo-csecal 
valve  to  the  hepatic  flexure,  and  about  four  and  one-half  hours  to 
reach  the  splenic  flexure. 

Secretion  of  the  large  intestine.  —  The  secretion  of  the  large 
intestine  is  alkaline,  contains  much  mucus,  and  does  not  contain 
any  enzymes.  Wlien  the  contents  of  the  small  intestine  pass 
the  ileo-caecal  valve,  they  still  contain  a  certain  amount  of 
unabsorbed   food   material.     This   remains    a  long  time  in   the 

1  Slow  peristalsis  will  cause  constipation,  and  is  often  associated  with  a  torpid 
liver.  As  bile  is  a  natural  stimulant  to  the  muscles  of  the  bowel,  an  insufficient 
quantity  may  result  in  slow  peristalsis. 


300  ANATOMY  FOR  NURSES  [Chap.  XV 

intestine,  and  since  it  contains  the  digestive  enzjines  received 
in  the  duodenum,  the  process  of  digestion  and  absorption 
continues. 

By  the  abstraction  of  all  the  soluble  constituents,  and  especially 
by  the  withdrawal  of  water,  the  liquid  contents  become,  as  they 
approach  the  rectum,  changed  into  a  firm  and  solid  mass  of  waste 
matters,  ready  for  ejection  from  the  body,  and  calK-d  feces. 

Action  of  bacteria  in  large  intestine.  —  Protein  putrefaction 
due  to  the  action  of  bacteria  is  a  constant  and  normal  occurrence 
in  the  large  intestine.  A  long  list  of  end  products  result  from 
this  putrefaction.  Some  are  given  off  in  the  feces,  others  are  ab- 
sorbed and  later  excreted  in  the  urine.  The  action  of  bacteria  is 
considered  of  doubtful  value.  It  is  possible  that  they  may  act 
upon  the  cellulose  of  vegetable  foods  and  render  it  useful  in  nu- 
trition. A  conservative  view  is  that  bacteria  confer  no  positive 
benefit,  but  under  normal  conditions  the  body  is  able  to  neutralize 
their  action. 

The  feces. — The  feces  consist  of:  (1)  the  undigested  and 
indigestible  parts  of  the  food,  (2)  the  products  of  bacterial  de- 
composition, (3)  great  quantities  of  bacteria  of  difi'erent  kinds, 
(4)  bile  and  other  secretions,  (5)  enzymes,  and  (6)  inorganic  salts. 
The  color  of  feces  is  due  to  the  presence  of  pigments  derived  from 
the  bile. 

Defecation.  —  The  anal  canal  is  guarded  by  an  internal  sphincter 
muscle  of  the  involuntary  type,  and  an  external  sphincter  that  is 
voluntary,  but  both  are  supplied  with  nerves  from  the  central 
nervous  system  and  consequently  defecation  is  a  voluntary  act. 
Normally  the  rectum  is  empty  until  just  before  defecation.  Various 
stimuli  (depending  on  one's  habits)  will  produce  peristaltic  action  of 
the  colon,  so  that  a  small  quantity  of  feces  enters  the  rectum. 
This  irritates  the  sensory  nerve  endings  and  causes  a  desire  to 
defecate.  The  voluntary  contraction  of  the  abdominal  muscles, 
the  descent  of  the  diaphragm,  and  powerful  peristalsis  of  the  colon 
all  combine  to  empty  the  colon  and  rectum. 

One  of  the  commonest  causes  of  constipation  is  the  retention 
of  feces  in  the  rectum  because  of  failure  to  act  on  the  desire  for 
defecation.  After  feces  once  enter  the  rectum  there  is  no  retro- 
peristalsis  to  carry  it  back  to  the  colon,  and  the  sense  of  irritation 
becomes  blunted.     The  desire  may  not  recur  for  twenty-four  hours, 


Chap.  XV]  DIGESTIVE   PROCESSES  301 

and  during  this  time  the  feces  continue  to  lose  water,  become 
harder,  and  more  diflficult  to  expeL 

ABSORPTION 

This  is  the  process  by  means  of  which  the  digested  food  is 
taken  from  the  intestines  and  carried  into  the  blood.  We  have 
now  to  consider  this  process,  for,  properly  speaking,  though  the 
food  may  be  digested  and  ready  for  nutritive  purposes,  it  is, 
until  it  passes  through  the  walls  of  the  alimentary  canal,  still 
practically  outside  the  body. 

Absorption.  —  Absorption  is  a  very  complex  process  and  may 
be  subdivided  into  a  physical  and  physiological  process.  The 
physical  process  consists  of  the  passage  of  the  digested  food  from 
the  intestines  into  the  blood-vessels,  and  is  governed  by  the  laws 
of  diffusion  and  osmosis.  The  physiological  process  consists  in 
the  building  up  of  the  end  products  of  protein  and  fat  digestion 
into  the  substances  found  in  the  blood.  This  process  of  reconstruc- 
tion is  not  understood,  but  is  dependent  on  the  living  epithelial 
cells  that  make  up  the  intestinal  walls. 

Paths  of  absorption.  —  There  are  two  paths  by  means  of  which 
the  products  of  digestion  find  their  way  into  the  blood  :  — 

(1)  By  the  capillaries  in  the  walls  of  the  stomach  and  intestines. 

(2)  By  the  lymphatics  in  the  walls  of  the  small  intestine  (the 
lacteals) . 

It  is  now  thought  that  absorption  through  the  stomach  is 
limited  to  small  quantities  of  such  substances  as  water,  glucose, 
and  salts.  This  means  that  the  greater  part  of  absorption  is  a 
function  of  the  small  and  large  intestines.  The  products  that 
result  from  the  digestion  of  proteins  and  carbohydrates  pass  into 
the  capillaries.  The  products  resulting  from  the  digestion  of 
fats  pass  into  the  villi  of  the  small  intestine. 


302 


ANATOMY  FOR  NURSES 


[Chap.  XV 


SUMMARY 

Digestion  —  Is  the  process  of  changing  food  into  products  capable  of 

absorption. 
Food  —  Substances  that  contain  elements  found  in  the  body,  or  furnish 

material  for  production  and  repair  of  tissue,  or  yield  energy. 


Classifica- 
tion 


Water 


.    f  Water. 

I  Mineral  matter  or  salts. 
(  Proteins. 
Organic    \  Carbohydrates. 
[  Fats. 

H2O.    About  66  per  cent  of  body  weight. 
Found  in  all  tissues. 
'  Supplies  fluid. 
Acts  as  solvent. 
Aids  in  elimination  of  waste. 


Mineral 
Matter 


'  of  sodium  and  potassium. 


magnesmm. 


Proteins 


Chloride 
Phosphate 
Sulphate 
Carbonate  , 

Phosphate  1    ,     ,  .  , 

^    ,        ^    ?  of  calcium  and 
Carbonate  J 

'  1.  To  maintain  alkalinity  of  body  fluids. 
2.  To  furnish  material  for  acidity  or  alkaUnity 
of  digestive  fluids. 
Function    {  3.  To  maintain  osmotic  pressure. 

4.  To  enter  into  bones,  teeth,  and  cartilage. 

5.  To   influence    elasticity    and    irritability    of 
muscles  and  nerves. 

Consist  of  C,  H,  N,  0 ;  S,  P,  and  other  elements  may  be 

present. 
Differ  from  carbohydrates  and  fats  in  having  nitrogen. 
Albumins. 
Caseinogen. 
Examples  I  Gluten. 
Legumin. 
,  Extractives. 


Chap.  XV] 


SUMMARY 


303 


Carbohy- 
drates 


Fats 


'  Consist  of  C,  H,  and  0,  the  two  latter  in  the  proportion  to 
form  water.     Include  sugars  and  starches. 

j  Glucose  or  dextrose  C6H12O6  [  Invert 

.     . ,     '1  Fructose  or  levulose  C6H12O6  |  sugar. 
chands       I  J 

Complex  f  Sucrose  or  cane  sugar  C12H22O11. 
or  Disac-  <  Lactose  or  milk  sugar  C12H22O11. 
charids       [  Maltose  or  malt  sugar  C12H22O11. 

'  Starch  (C6Hio05)w. 
Poly  sac-     J  Cellulose  (C6Hio05)n. 
charids         Glycogen  (C6Hio05)n. 
.  Dextrin  (C6Hio05)/i. 

'  Consist  of  C,  H,  and  0. 

Made  from  one  molecule  of  glycerine  and  three  molecules  of 
fatty  acid. 

Fats  are  liquid  at  body  temperature. 

Soluble  in  ether,  chloroform,  and  hot  alcohol. 
.  Decompose  to  give  glycerine  and  fatty  acids. 

Organic  foods  are  not  soluble,  hence  necessity  for  digestion. 
Inorganic  foods  are  soluble,  and  are  absorbed  directly. 

Mastication. 
Deglutition. 

Peristaltic  action  of  oesopha- 
Mechanical         I      gus. 

Peristaltic  action  of  stomach. 
Movements  of  intestines. 
Defecation. 
'  Splitting  of  complex  molecules 
into  simple  ones,  with  ab- 
Chemical  {      sorption  of  water. 

Process  of  hydrolysis  that  is 
dependent  on  enzymes. 

An  enzyme  is  produced  by  living  cells  and  acts  by  catalysis. 
Enzymes    {      Its  action  is  specific,  it  requires  a  medium  of  definite  reac- 
tion, and  the  products  must  be  removed. 


Digestion 


Processes 


304  ANATOMY  FOR  NURSES  [Chap.  XV 

LIST  OF  DIGESTIVE  FLUIDS  AND  CHIEF  ENZYMES 


Digestive  Fluids 

Enzymes 

Functions 

Saliva 

Ryalin 

Changes  starch  to  dextrin  and 
sugar  (maltose). 

Gastric  Juice 

Pepsin 

Changes  proteins  into  proteoses 
and  peptones  in  an  acid  medium. 

Gastric  Juice 

Rennin 

Curdles  the  caseinogen  of  milk. 

Pancreatic  Juice 

Trypsin 

Continues  action  of  pepsin, 
splits  proteoses  into  peptones 
and  amino-acids.  Requires  al- 
kaline or  neutral  medium. 

Pancreatic  Juice 

Diastase 

Changes  starch  to  dextrin  and 
sugar  (maltose). 

Pancreatic  Juice 

Lipase 

Splits  fats  to  fatty  acids  and 
glycerine. 

Succus  Entericus 

Erepsin 

Splits    peptones     into     simplex 

products. 

Sucrase 

Changes  sucrose  to  invert  sugar. 

Succus  Entericus 

Inverting  < 

Maltase 

Changes  maltose  to  dextrose. 

Lactase 

Changes  lactose  to  dextrose. 

BUe 

No  enzyme 

Splits  fats  into  fatty  acids  and 

glycerine.     Assist  in  saponifica- 

tion and  aids  in  absorption. 

Mastication  (chewing) . 
Insalivation  (mixing  with  saliva). 

Secreted  by  sali 
vary  glands 


Changes 
Food 

under- 
goes in 
Mouth 


Saliva 


and  mucous 
I  Submaxillary  \  glands  of 
I  Subungual       J  mouth. 
L  Reflex  stimulation. 
2.  Psychical. 
Consists  of  water,  mucus,  and  enzjTne  —  ptyalin. 
Specific  gravity  L004-1.00S.     Alkaline  reaction. 
One  or  two  quarts  in  24  hours. 


Result  of 


Functions 


Deglutition  (swallowing). 


1.  Assists  in  speech. 

2.  Assists  in  mastication 

deglutition. 

3.  Assists  in  taste. 

4.  Acts  upon  starch. 


and 


Chap.  XV] 


SUMMARY 


305 


Stomach 
Digestion 


o 

H 
CO 


Gastric 
juice 


Peristaltic  action  of  stomach. 

Time  required  for  stomach  digestion  about  5  hours. 

Secretion  of  gastric  juice  \  ^^^  ]^^' 

[  Chemical  — •  Secretin. 

Secreted  by  glands  of  stomach  (  ^^P*^^- 

I  Pyloric. 

About  15  pints  in  24  hours.     Pale  yellow  liquid 

Acid  reaction  due  to  free  hydrochloric  acid. 

r  Pepsin. 
Enzymes  <  Rennin. 

I  Gastric  lipase. 


Movements  of  small  intestine  (  Pen^^^l^ic. 

I  Rhythmic  segmentation. 

Secretion  of  pancreatic  juice  (  ^f^^^^.^^^)- 

I  Chemical  —  secretin. 

Secreted  by  pancreas,  discharged  into  small 

intestine  during  digestion. 

Pancreatic  I  Viscid  fluid,  alkaline  reaction, 

juice        1  f  Trypsin. 

Enzymes  \  Diastase. 

I  Lipase. 


Small 
Intestine 


Succus 
entericus 


Intestinal  or  Lieber- 
kuhn's. 


2.  Duodenal    or    Brun- 


Enzymes 


Bile 


Bacteria 


Secreted  by  glands 
found  in  intes- 
tines 

ner's. 

Yellowish  fluid,  alkaUne  reaction. 
f  Erepsin. 
I  Inverting. 

'  Secreted  by  liver,  stored  in  gall-bladder,  dis- 
charged into  small  intestine  during  diges- 
tion. 
Golden  brown  or  greenish  liquid  with  alkaline 

reaction. 
About  1  quart  in  24  hours. 

f  1.  Splits  up  neutral  fats. 

2.  Aids  in  absorption  of  fats. 

3.  Antiseptic  action  on  intestinal 
Action      <!  contents. 

4.  Excretes  products  of  disinte- 
gration of  haemoglobin. 

,  5.  Mild  laxative. 
f  Decompose  carbohydrates. 
I  Little  or  no  effect  on  proteins. 


306 


ANATOMY  FOR  NURSES 


[Chap.  XV 


I-} 

<! 

H 
CO 

H 


'  Movements  of  large  intestine  —  antiperistaltic. 
Time  required  for  food  to  pass  from  caecum  to  splenic 
flexure  about  6^  hours. 

(  Alkaline  reaction. 
Secretion    <  Contains  a  great  deal  of  mucus. 
[  No  enzymes. 

r  Decomposition  of  proteins  constant. 
Large        I  Bacteria      <  Possible  action  on  cellulose. 
Intestine  )  i  Benefit  doubtful. 

Undigested  and  indigestible  portions  of  food. 
Products  of  bacterial  decomposition. 
Feces  {  Great  quantities  of  bacteria. 

Bile  and  other  secretions. 
Enzymes  and  inorganic  salts. 
Defecation  —  This  term  is  appUed  to  the  act  of  expelling 
the  feces  from  the  rectum. 

Process  of  taking  up  digested  food-stuffs  and  carrying  them 
to  the  blood. 

f  Physical  —  Diffusion  and  osmosis. 
Physiological  —  Reconstruction   of   end   prod- 
ucts of  digestion  into  substances  found  in  the 
blood. 

1.  Capillaries  in  the  walls  of  the  stomach  and 
intestines.  This  blood  is  carried  by  means 
of  portal  vein  to  liver,  from  liver  by  he- 
patic veins  to  inferior  vena  cava,  thence 
to  right  auricle. 

2.  Lymphatics  in  the  walls  of  small  intestine 
(lacteals)  absorb  digested  fats  and  empty 
into  chyle  cistern  of  thoracic  duct,  superior 
vena  cava,  and  right  auricle  of  heart. 


Absorption 


Two  parts 


Paths  of 
absorption 


CHAPTER  XVI 

METABOLISM  — DUCTLESS   GLANDS 

The  nutritive  processes  in  the  human  body  include:  (1)  the  re- 
ception and  digestion  of  food,  followed  by  absorption  of  the  differ- 
ent food  products,  and  the  distribution  of  these  products  to  all  the 
cells  by  the  circulating  liquids  of  the  body;  (2)  the  absorption 
of  oxygen  by  the  circulating  liquids  in  the  lungs,  its  distribution 
to  all  the  cells  of  the  body,  and  its  union  with  the  constituents  of 
the  cells.  We  have  studied  digestion  and  absorption,  and  our 
special  problem  in  this  chapter  is  metabolism. 

Metabolism.  —  This  term  includes  all  the  changes  that  occur  in 
digested  food-stuffs  from  the  time  of  their  absorption  until  their 
elimination  in  the  excretions. 

Metabolic  changes.  —  The  most  important  chemical  changes 
that  occur  in  metabolism  are  as  follows  :  — 

(1)  The  cells  take  from  the  blood  the  substances  which  they 
require  for  repair  and  growth,  and  build  it  up  into  protoplasm. 
This  involves  the  conversion  of  non-living  material  into  the 
living  protoplasm  of  the  cells. 

(2)  Oxidation,  or  the  union  of  oxj^gen  with  the  constituents  of 
the  cells,  resulting  in  the  release  of  energy  and  the  breaking  down 
of  complex  substances  into  simpler  products. 

(3)  Some  of  the  simpler  products  that  result  from  oxidation  are 
acids.  These  acids  must  be  eliminated  or  decomposed,  as  all  the 
digestive  fluids  of  the  body,  with  the  exception  of  gastric  juice,  are 
alkaline  or  neutral,  and  this  condition  is  essential  to  nutrition  and 
even  to  the  immediate  continuance  of  life,  (a)  Some  of  the  w^eaker 
acids  are  eliminated  in  the  urine;  one,  carbonic  acid  (H2CO3), 
is  a  very  unstable  compound  and  breaks  down  to  form  water 
(H2O)  and  carbon  dioxide  (CO2).  (b)  When  proteins  are  oxidized, 
sulphur  is  set  free.  This  sulphur  (S)  unites  with  water  (H2O)  and 
ox^^gen  (O2)  to  form  sulphuric  acid  (H2SO4).  Sulphuric  acid  is 
promptly  neutralized  by  the  alkalies  present  in  the  tissues,  so  that 
the  body  never  contains  sulphuric  acid,  but  does  contain  sul- 

307 


308  ANATOMY.  FOR  NURSES  [Chap.  X\  1 

phates  and  water,  which  result  from  the  process  of  neutralization. 
(See  page  8.) 

(4)  The  conversion  of  glucose  into  glycogen,  and  the  reconver- 
sion of  glycogen  into  glucose. 

(5)  The  conversion  of  glucose  into  fat.  This  is  a  chemical 
change  that  is  not  well  understood,  but  various  experiments  have 
satisfied  physiologists  that  the  tissues  can  produce  fat  from  supar. 

These  changes  can  be  classified  under  two  heads:  (1)  anab- 
olism,  or  the  building-up  processes,  and  (2)  katabolism,  or  the 
splitting  of  complex  substances  into  simpler  ones. 

Functions  of  metabolism.  —  Metabolic  changes  serve  two  im- 
portant   purposes:    (1)  the   repair  and    growth   of   tissue,   and 

(2)  the  release  of  chemical  energy  in  the  form  of  heat,  nervous 
activity,  and  muscular  activity. 

Factors  which  promote  metabolic  changes.  —  The  factors  which 
produce  metabolic   changes  are:    (1)  enzjTnes,   (2)  oxj'gen,  and 

(3)  internal  secretions.  It  was  formerly  taught  tliat  the  oxA'gen 
absorbed  from  the  lungs  was  responsible  for  all  the  processes  of 
oxidation  that  occur  in  the  body.  More  accurate  study  has  dem- 
onstrated that  while  oxj'gen  is  an  important  factor,  it  is  only  one, 
and  the  enzymes  that  are  present  in  nearly  all  the  body  tissues 
are  capable  of  decomposing  complex  materials  into  simpler  sub- 
stances. Moreover,  it  is  generally  considered  that  the  action 
of  the  tissue  enzymes  comes  first  and  causes  decomposition  by 
hydrolysis,  then  other  enz^^Tnes  termed  oxidases  activate  the  pro- 
cess of  oxidation. 

METABOLISIM   OF  FATS 

We  have  traced  the  digested  fat  or  chyle  into  the  lacteals. 
From  the  small  lacteals  it  must  find  its  way  through  the  larger 
lymphatics  in  the  mesentery  to  the  thoracic  duct,  and  then 
through  the  thoracic  duct  to  the  blood.  This  fat  is  carried  by  the 
blood  to  all  the  different  parts  of  the  body,  and  the  tissues  slowly 
take  it  out  as  they  need  it  in  their  metabolic  processes.  Within 
the  tissues  it  serves  as  a  fuel  and  is  oxidized  to  supply  the  energy 
needs  of  the  cells.  If  fat  is  burned  outside  the  body,  heat  is  lib- 
erated, and  the  waste  products  are  carbon  dioxide  and  water. 
This  process  is  similar  to  the  one  that  takes  place  in  the  body. 
Fat  that  is  not  required  for  the  production  of  energy  is  stored  up 
in  certain  parts  of  the  body,  but  not  all  the  adipose  tissue  found  in 


Chap.  XVI]  METABOLISM  309 

the  body  is  derived  from  fats,  as  excess  carbohydrates  are  also 
stored  as  fat. 

Function  of  fats.  —  The  main  function  of  fat  is  to  serve  as  fuel 
and  yield  heat  and  energy.  The  fat  that  is  stored  in  the  form  of 
adipose  tissue  constitutes  an  important  reserve  fund  to  be  drawn 
upon  in  time  of  need.  In  diseased  conditions  or  when  the  supply 
of  food  is  insufficient,  the  body  oxidizes  first  the  glycogen  stored  in 
the  liver  and  then  the  fats  stored  in  adipose  tissue,  and  the  proteins 
of  the  tissues  themselves.  If  the  supply  of  fat  is  large,  it  follow^s 
that  the  protein  tissues  will  be  protected.  (For  other  functions, 
see  page  39.) 

The  cause  of  obesity.  —  This  condition  is  usually  caused  by 
eating  more  carbohydrate  and  fat  than  the  body  needs.  The 
excess  is  stored  as  glycogen  and  adipose  tissue.  The  needs  of  dif- 
ferent individuals  vary,  depending  on  their  mode  of  life,  and  on 
their  capacity  to  oxidize  food  materials,  so  that  a  diet  which  will 
give  an  excess  to  one  individual  may  in  the  body  of  another  be  en- 
tirely consumed.  A  sedentary  life  and  absence  of  worry  lessen  the 
oxidation  of  food  products  and  increase  the  tendency  to  take  on 
flesh,  while  a  very  active  muscular  life  has  the  opposite  effect. 

METABOLISM   OF   CARBOHYDRATES 

During  the  process  of  digestion  all  the  carbohydrates  are 
changed  to  glucose,  absorbed  into  the  blood,  and  carried  to  the 
liver.  The  liver  cells  take  this  glucose  from  the  blood,  and  by  put- 
ting together  a  number  of  molecules  and  withdrawing  water,  the 
soluble  glucose  is  changed  to  insoluble  glycogen,  which  is  stored 
in  the  liver  cells  and  the  muscles.  In  thus  storing  up  glycogen 
and  doling  it  out  as  needed,  the  liver  helps  to  maintain  the  normal 
quantity  of  glucose  — 0.1  to  0.15  per  cent  —  in  the  blood.  An 
increased  amount  of  glucose  in  the  blood,  resulting  from  the  in- 
gestion of  a  large  amount  of  sugar,  may  provide  more  glucose  than 
the  liver  can  take  care  of,  and  the  excess  is  eliminated  in  the  urine. 
A  permanent  increase  in  the  amount  of  sugar  in  the  blood  is  irri- 
tating to  the  tissues  and  acts  as  a  poison,  so  that  the  liver  by  main- 
taining the  normal  quantity  protects  the  tissues  from  such  irrita- 
tion. 

Factors  controlling  the  metabolism  of  carbohydrates.  —  The 
metabolism  of  carbohvdrates  is  under  the  control  of  the  nervous 


310  ANATOMY  FOR   NURSES  [Chap.  XVI 

system,  but  the  enzymes  contained  in  the  Hver  and  the  internal 
secretion  of  the  pancreas,  and  some  of  the  ductless  glands  play  a 
very  important  part. 

Function  of  carbohydrates.  —  The  oxidation  of  glucose  serves 
the  following  purposes:  (1)  It  furnishes  the  main  if  not  the  only 
source  of  energy  for  muscular  work,  and  for  all  the  nutritive 
processes  of  the  body.  (2)  It  furnishes  an  important  part  of 
the  heat  needed  to  maintain  the  body  temperature.  (3)  It  pre- 
vents oxidation  of  the  body  tissues,  because  it  constitutes  a  re- 
serve fund  that  is  the  first  to  be  drawn  upon  in  time  of  need. 
(4)  An  excess  of  carbohydrates  over  and  above  what  can  be 
stored  as  glycogen  in  the  liver  and  tissues  is  converted  into  adipose 
tissue. 

Waste  products  of  carbohydrate  metabolism.  —  The  waste 
products  resulting  from  the  oxidation  of  glucose  are  carbon 
dioxide  (CO2)  and  water  (H2O).  This  process  is  thought  to  be 
comparable  to  the  fermentation  of  sugar  outside  the  body,  and 
the  same  substances  are  formed,  viz.  alcohol,  acids,  carbon 
dioxide,  and  water. 

METABOLISM  OF  PROTEINS 

The  substances  resulting  from  the  digestion  of  proteins,  i.e. 
peptones,  polypeptids,  and  amino-acids  are  not  found  in  the 
blood  to  any  extent,  because  during  the  passage  of  these  sub- 
stances through  the  intestinal  walls  they  are  changed  to  serum- 
albumin  and  serum-globulin.  The  tissues  take  these  substances 
from  the  blood  and,  by  a  process  that  is  not  well  understood, 
convert  them  into  protein  material  of  the  kind  found  in  any 
particular  tissue.  In  this  way  broken-down  tissue  is  replaced 
and  new  tissue  is  formed.  The  protein  substances  absorbed  are 
usually  in  excess  of  what  is  needed  for  repair  and  tissue  building. 
This  excess  is  acted  upon  by  the  liver,  and  the  protein  molecule 
is  split  up  into  two  parts.  One  part  is  known  as  the  ammonia 
molecule,  and  contains  hydrogen  and  nitrogen.  This  is  subse- 
quently converted  into  urea  and  similar  substances,  which  are 
carried  by  the  blood  to  the  kidneys  and  excreted  in  the  urine- 
The  second  part  may  be  either  oxidized  directly,  or  built  up  into 
carbohydrates  and  fats  which  eventually  become  oxidized,  and  in 
either  case  heat  and  energy  are  liberated. 


Chap.  XVI]  METABOLISM  311 

Classification  of  proteins.  —  Proteins  vary  in  their  constituents  and 
vary  in  their  nutritive  value.  Because  of  this  they  are  classed  as 
adequate  and  inadequate  proteins.  Adequate  proteins  contain  all 
the  constituents  for  the  maintenance  and  growth  of  the  body.  I?i- 
adequafe  proteins  furnish  material  for  energy  needs,  but  not  for 
the  repair  of  tissue  waste.  Gelatine  is  an  example  of  an  inade- 
quate protein.  It  is  easily  digested  and  absorbed,  undergoes 
oxidation,  which  results  in  the  liberation  of  energy  and  the  produc- 
tion of  urea,  carbon  dioxide,  and  water,  but  it  does  not  supply  the 
material  needed  for  the  repair  of  tissue  waste. 

Function  of  proteins.  —  The  main  function  of  proteins  is  to  build 
up  tissue,  and  they  are  the  one  class  of  foods  capable  of  doing  this. 
In  addition  they  serve  the  same  purpose  as  carbohydrates  and  fats 
and  may  even  be  converted  into  adipose  tissue. 

Nitrogen  equilibrium,  —  The  protein  molecules  are  charac- 
terized by  containing  nitrogen  (some  say  as  much  as  16  per  cent). 
After  the  metabolism  of  protein,  nitrogen  is  eliminated  chiefly  in 
the  urine,  and  to  a  limited  extent  in  the  feces  and  sweat.  The 
body  is  said  to  be  in  nitrogen  equilibrium  when  the  amount  of 
protein  nitrogen  taken  into  the  body  is  equal  to  the  amount  elim- 
inated in  the  excreta.  If  there  is  a  plus  balance  in  favor  of  the 
food,  it  means  that  protein  is  being  stored  in  the  body,  and 
this  is  an  ideal  condition  during  the  period  of  growth,  or  con- 
valescence from  wasting  illness.  If  the  balance  is  minus,  the 
body  must  be  losing  protein,  but  under  normal  conditions  this 
does  not  occur. 

Heat  value  of  food.  — -  The  supply  of  heat  needed  to  main- 
tain the  body  temperature  comes  from  the  processes  of  oxidation. 
The  heat  produced  is  estimated  in  terms  of  calories  ^  and  is  meas- 
ured with  the  calorimeter.  There  are  two  kinds  of  calories,  i.e. 
small  and  large.  A  small  calorie  is  the  quantity  of  heat  necessary 
to  raise  one  gram  of  water,  one  degree  centigrade  in  temperature. 
A  large  calorie  is  the  quantity  of  heat  necessary  to  raise  one  thou- 
sand grams  of  water  one  degree  centigrade.  The  large  calorie  is 
the  one  referred  to  in  physiology.  It  has  been  estimated  that  each 
gram  of  fat  yields  about  9.3  calories,  each  gram  of  carbohydrate 
yields  about  4.1  calories,  and  each  gram  of  protein  yields  about  4.1 
calories, 

1  See  page  12, 


312  ANATOMY   FOR   NURSES  [Chap.  XVI 

The  amount  of  food  necessary  for  normal  nutrition.  —  In  a 
normal  condition  the  main  object  of  food  is  :  (1)  to  furnish  the  ma- 
terial for  the  repair  of  tissue,  and  (2)  to  furnish  material  for  the 
heat  produced  and  the  muscular  and  other  work  done.  The  most 
important  factors  influencing  the  amount  of  food  required  are 
activity,  age,  size,  sex,  and  climate.  The  greater  the  amount 
of  nuiscular  work,  the  greater  the  amount  of  food  rccjuired. 
Children  need  more  food  in  proportion  to  their  weight  than 
adults,  because  they  are  more  active,  and  in  addition  must 
provide  for  the  growth  of  new  tissue.  Increased  age  usually  means 
less  active  life  and  thus  less  food  is  required.  A  large  person 
requires  more  food  because  the  greater  amount  of  tissue  requires 
the  expenditure  of  more  energy  in  all  the  nutritive  processes. 
Women  as  a  riile  require  less  food  than  men,  because  they  are 
smaller,  and  possibly  less  energetic  in  their  movements.  In  an 
extremely  cold  climate  more  food  is  required  for  heat  production 
in  order  to  make  up  for  the  loss  of  heat  from  the  body.  It  is  ordi- 
narily estimated  that  the  daily  diet  should  yield  2400  calories  for 
an  individual  weighing  about  60  kilograms  (130  lbs.),  that  is,  40 
calories  for  each  kilogram  of  body  weight. 

In  computing  the  proportion  of  different  foods  to  be  used  the 
total  number  of  calories  is  divided  into  fifths ;  sufficient  protein 
is  allowed  to  give  one-fifth  ;  sufficient  fat  to  give  one-  to  two-fifths, 
and  sufficient  carbohydrates  to  give  two-  to  three-fifths. 

Ranke's  diet  is  as  follows : 

Protein  100  gm.  =  410  calories. 

Fats  100  gm.  =  930  calories. 

Carbohydrates  240  gm.  =  984  calories. 

Total  2324  calories. 

There  is  no  approach  to  unanimity  in  the  amounts  required ; 
thus  Moleschott  would  give  130  grams  of  protein,  while  Chittenden 
thinks  GO  grams  of  protein  sufficient. 

Ranke's  diet  is  given  because  it  is  the  simplest,  other  diets  by 
other  authors  may  be  just  as  good  or  even  better.  For  further 
details  some  standard  book  on  dietetics  should  be  consulted. 

For  a  healthy  person  leading  a  normal  life  appetite  and  experi- 
ence seem  safe  guides  by  which  to  control  the  diet.  They  will  at 
least  prevent  undernutrition,  and  the  consequent  lessening  of  the 


Chap.  XVI]  DUCTLESS   GLANDS  313 

body's  natural  powers  of  resistance  to  disease.  The  opposite 
danger  of  overeating  is  a  real  one,  because  an  excess  of  food  puts 
unnecessary  strain  upon  the  organs  of  nutrition  and  excretion,  and 
favors  the  formation  of  excessive  adipose  tissue.  Excess  of  proteins 
overloads  the  system  with  the  products  of  intestinal  putrefaction. 
Excess  of  carbohydrates  causes  flatulence,  due  to  fermentation  of 
these  foods.  It  is  thought  that  an  excess  of  fat  interferes  with 
digestion  by  retarding  the  secretion  of  gastric  juice. 

DUCTLESS  GLANDS 

The  ductless  glands  form  a  group  of  organs  that  produce  secre- 
tions, called  internal  secretions,  which  leave  the  gland  by  the  blood 
or  lymph,  and  not  by  means  of  a  duct.  Many  of  the  glands  that 
possess  ducts  and  form  an  external  secretion  form  an  internal 
secretion  as  well,  but  these  are  not  classed  as  ductless,  because  the 
external  secretion  is  carried  out  of  the  gland  by  means  of  a  duct, 
though  the  internal  secretion  passes  into  the  blood  or  lymph  just 
as  in  the  ductless  glands.  The  function  of  the  ductless  glands  is 
intimately  connected  with  the  purpose  of  the  internal  secretions, 
and  this  is  very  imperfectly  understood,  because  of  the  impossibil- 
ity of  securing  the  internal  secretions  in  a  state  of  purity,  i.e.  free 
from  blood  or  lymph.  As  the  result  of  many  experiments  it  is 
considered  probable  that  the  internal  secretions  contain  hormones 
which  act  as  chemical  stimuli  and  to  a  limited  extent  assist  in  the 
correlation  of  the  activities  of  different  organs. 

The  most  important  ductless  glands  are :  — 

(1)  The  Thyroid. 

(2)  The  Parathyroids. 

(3)  The  Thymus. 

(4)  The  Adrenals  (supra-renal  capsules). 

(5)  The  Hypophysis. 

(6)  The  Epiphysis. 

(7)  The  Carotid  glands. 

(8)  The  Coccygeal  glands. 

(1)  The  thyroid. — The  thyroid  is  a  small,  flat  gland  lying 
against  the  fore  part  of  the  trachea,  below  the  thyroid  cartilage. 
It  is  of  a  deep  red  color,  weighs  about  an  ounce  (30  grams)  or 
more,  and  consists  of  two  lateral  lobes  connected  at  their  lower 


314 


ANATOMY  FOR  NURSES 


[Chap.  XVI 


parts  by  an  isthmus.  The  lobes  are  broadest  below  and  taper 
to  a  point  above.  Small  masses  of  thyroid  tissue  are  sometimes 
found  along  the  trachea  as  far  down  as  the  heart.  They  are  called 
accessory  thjrroids.  Comparatively  little  is  known  about  the  action 
of  the  thyroid  secretion,  but  much  clinical  evidence  supports  the 


RIGHT    LOBE    OF. 
THYROID    BODY 


.    PYRAMID    OF 
THYROID    BODY 


Fig.  163.  —  The  Thyroid  Body  axd  thk  Related  Blood-vessels.     (Gerrish.) 

belief  that  it  is  necessary  for  the  normal  growth  and  functions  of 
almost  all  the  tissues  of  the  body. 

Cretinism  is  a  condition  caused  by  congenital  defects  of  the 
thyroid  or  atrophy  occurring  in  early  life.  The  growth  of  the 
skeleton  ceases  and  there  is  complete  arrest  of  mental  development. 
Children  so  afflicted  may  live  for  many  years,  but  at  twenty-five 
or  thirty,  they  have  the  intelligence  of  a  child  of  four  or  five,  and 
present  a  childish  appearance. 

Myxcedema  is  a  disturbed  condition  of  metabolism  that  follows 
the  removal  or  atrophy  of  the  gland.  The  individual  so  afflicted 
presents  a  peculiar  appearance,  as  the  subcutaneous  connective 
tissue  becomes  thickened,  so  that  the  face  and  hands  are  swollen 


Chap.  XVI] 


DUCTLESS   GLANDS 


315 


and  puffy.  The  mental  faculties  become  blunted  and  idiocy  re- 
sults unless  proper  treatment  is  instituted. 

Cretinism  and  myxoedema  are  both  supposed  to  be  due  to  a  lack 
of  the  internal  secretion  of  the  thyroid,  and  much  success  has 
followed  the  administration  of  thyroid  extract  in  various  ways. 

Goitre  is  a  condition  in  which  the  gland  is  enlarged,  but  the  se- 
cretion may  not  be  interfered  with. 

Exophthalmic  goitre  is  a  disease  characterized  by  extreme  ner- 
vousness, quickened  heart  action,  protruding  eyeballs,  and  goitre. 
It  is  caused  by  an  overabundant  production  of  thyroid  secretion, 
due  to  enlargement  and  over  acti^-it^'  of  the  dand. 


Fig.  164.  —  The  Thymus,  the  Sternal  and  Costal  Cartilages  having  been 
Removed.      (Gerrish.) 


(2)  The  Parathyroids.  —  Embedded  in  the  surface  of  each 
lateral  lobe  of  the  thyroid  are  two  little  masses,  each  about  one- 
fourth  inch  (6.25  mm.)  in  diameter.  They  are  solid  accumula- 
tions of  epithelioid  cells,  invested  with  a  tunic  of  areolar  tissue 
and  well  supplied  with  blood-vessels.  The  function  of  the  para- 
thyroids is  supposed  to  consist  in  neutralizing  toxic  substances 
found  elsewhere  in  the  body. 

(3)  The  Thymus.  —  The  thymus  consists  of  two  large  masses 
of  glandular  tissue  situated  below  the  thyroid  and  in  front  of  the 


316  ANATOMY   FOR   NURSES  [Chap.  XVI 

trachea.  It  is  described  as  a  temporary  organ  of  foetal  and  infantile 
life.  It  appears  at  the  end  of  the  second  month  of  intra-uterine 
life  and  continues  to  grow  until  a  child  is  two  or  three  years  old. 
At  that  time  it  weighs  about  six  drachms.  Thereafter  it  atroj)hies 
and  disappears,  except  for  some  shreds  of  tissue  still  present  at 
the  age  of  puberty.  The  function  of  this  gland  is  not  known,  but 
it  is  thought  to  have  a  definite  connection  with  growth  and  with 
the  development  of  the  reproductive  organs. 

(4)  The  adrenals  or  supra-renal  capsules.  —  The  adrenals  are 
small  flattened  bodies  of  a  yellowish  color  wliich  are  ])laced  one 
above  each  kidney.  They  are  usually  classified  with  the  ductless 
glands,  as  they  have  no  excretory  duct,  but  are  sometimes  classed 
with  the  organs  of  the  central  nervous  system,  as  they  contain  a 
great  deal  of  nerve-tissue.  Each  organ  weighs  about  one  tlrachm, 
and  is  invested  by  a  fibrous  capsule  which  sends  fibres  into  the 
glandular  substance ;  these  fibres  form  a  framework  for  the  soft, 
I)ulpy  substance  of  the  gland,  and  within  the  spaces  of  the  frame- 
work are  groups  of  cells.     (See  Fig.  KHL) 

The  adrenals  are  plentifully  supplied  witli  ])lood-vcssels  and 
lymphatics,  and  they  contain  some  striking  coloring  matters. 
In  diseases  of  these  organs,  the  skin  frequently  becomes  "  bronzed  " 
from  an  increase  of  pigment  or  coloring  matter. 

Function.  —  The  adrenals  produce  an  internal  secretion  which 
is  called  adrenalin.  The  function  of  this  secretion  seems  to  be  con- 
nected with  maintaining  the  tone  of  the  heart  and  blood-vessels. 
It  is  still  a  question  whether  this  maintenance  of  tone  is  the  result 
of  the  secretion  acting  directly  on  the  tissues  of  the  heart  and  blood- 
vessels, or  indirectly  on  the  nerve  centres.  Removal  of  these 
glands  results  in  such  a  loss  of  tone  that  death  follows. 

Adrenalin  extract  is  made  from  the  supra-renal  capsules  of  ani- 
mals, and  is  used  as  a  heart  stimulant  to  improve  the  tone  of  the 
heart  and  blood-vessels,  also  in  hemorrhage  to  constrict  the  vessels. 

(5)  The  hypophysis.  —  The  hypophysis,  also  called  the  pitui- 
tary body,  is  of  an  ovoid  form,  a  reddish  gray  color,  and  consists  of 
two  lobes.  The  anterior  lobe  is  larger  and  distinctly  glandular, 
the  posterior  lobe  is  smaller  and  composed  of  nerve  cells  and 
fibres. 

The  pituitary  is  lodged  in  a  depression  of  the  middle  portion 
of  the  sphenoid  bone,  and  is  firmly  held  in  place  by  the  dura  mater. 


Chap.  XVI]  DUCTLESS   GLANDS  317 

Little  is  known  of  the  function  of  this  gland,  but  the  results  of 
various  experiments  justify  the  belief  that  the  secretion  of  both 
the  anterior  and  posterior  lobes  has  an  important  influence  upon 
metabolism.  The  secretion  of  the  anterior  lobe  is  connected  with 
growth,  particularly  of  the  skeleton.  The  secretion  of  the  pos- 
terior lobe  has  a  specific  effect  upon  the  organs  of  circulation,  in- 
creases the  secretion  of  urine  and  milk,  and  is  connected  in  some 
way  with  the  metabolism  of  carbohydrates.  There  seems  to  be 
an  inter-relation  between  the  hypophysis,  and  the  pancreas,  adre- 
nals, and  thyroid. 

Gigantism,  or  excessive  growth,  and  dwarfism,  or  underdevelop- 
ment, are  thought  to  be  due  to  abnormal  conditions  of  this  gland 
in  early  life.  In  later  life  abnormal  conditions  are  attended  with 
enlargement  of  the  bones  of  the  extremities  and  the  features  of 
the  face,  a  condition  known  as  acromegaly. 

(6)  The  epiphysis.  —  The  epiphysis  or  pineal  body  is  a  small 
reddish  gray  body  located  in  the  third  ventricle  of  the  brain. 
In  early  life  it  is  glandular  and  attains  its  maximum  growth  about 
the  seventh  year.  After  this  period,  and  particularly  after  puberty, 
it  decreases  in  size,  and  the  glandular  tissue  is  replaced  by  fibrous 
tissue.  It  is  thought  that  in  early  life  the  gland  furnishes  a  se- 
cretion that  inhibits  growth,  and  restrains  the  development  of  the 
reproductive  glands. 

(7)  The  carotid  glands.  —  They  are  so  named  because  each  is 
situated  in  the  bifurcation  of  a  common  carotid  artery.  They 
are  composed  of  nodules,  each  of  which  is  a  mass  of  epithelial 
cells,  among  which  are  large  capillaries.  They  are  covered  by  a 
fibrous  capsule. 

(S)  Coccygeal  gland.  —  The  coccygeal  gland  is  situated  in  front 
of  the  tip  of  the  coccyx.  It  is  co^•e^ed  by  fibrous  tissue  and  com- 
posed of  epithelial  cells. 

SPLEEN 

Some  authorities  class  the  spleen  with  the  ductless  glands ; 
other  authorities  question  this,  as  it  has  not  been  possible  to  de- 
monstrate that  it  furnishes  an  internal  secretion.  It  is  directly 
beneath  the  diaphragm,  l)ehind  and  to  the  left  of  the  stomach. 
It  is  covered  by  a  portion  of  the  peritoneum,  the  serous  membrane 
covering  the  viscera  of  the  abdomen.  It  is  bean-shaped,  convex  on 
the  outer  surface,  concave  on  the  inner,  and  weighs  usually  from 


318 


ANATOMY   FOR   NURSES  [Chap.  XVI 


five  to  eight  ounces  (150  to  240  grams).  Beneath  the  serous 
coat  it  is  covered  by  a  fibrous  and  muscular  capsule  which  sends 
fibrous  bands  (trabecules)  to  form  a  network  in  the  interior  of  the 
organ.  The  meshes  of  this  fibrous  framework  are  filled  with  a 
substance  called  spleen  pulp,  which  is  dark  red  in  color,  and  consists 
of  blood  containing  splenic  cells,  leucocytes,  red  corpuscles  of  nor- 
mal appearance,  and  others  variously  changed.     This  soft  red  pulp 

is  dotted  with  whitish 
specks,  which  are  small 
masses  of  lymphoid  tissue, 
and  are  called  the  Mal- 
pighian  corpuscles  of  the 
spleen. 

Blood  supply.  —  Blood 
is  supplied  to  the  spleen 
by  the  splenic  artery, 
which  enters  the  concave 
side  of  the  spleen  at  a  de- 
pression called  the  hilus. 
The  arrangement  of  the 
blood-vessels  is  peculiar  to 
this  organ.  The  splenic 
artery  divides  into  several 
branches  before  entering 
the  organ,  and  after  enter- 
FiG.  165.  —  The   Spleen,    showixg   the  ing,    rapidly    divides    into 

Sr^nn^v.^^?      ReNAL      SURFACES      AND      ^HE  ||  |  W^jen  thc 

Blood-vessels.     (Gernsh.) 

minute  arteriole  stage  is 
reached,  the  vessels  terminate,  and  the  blood  escapes  into  the 
spleen  pulp.  The  blood  is  collected  from  the  pulp  by  thin- 
walled  veins,  which  unite  to  form  the  splenic  vein.  The  splenic 
vein  unites  with  the  superior  mesenteric  to  form  the  portal  vein, 
and  carries  the  ])lood  to  the  liver. 

Function.  —  The  functions  of  the  spleen  are  imperfectly  under- 
stood, but  it  is  usually  credited  with  the  following :  — 

(1)  The  formation  of  leucocytes.  The  reason  for  this  is  that  the 
blood  which  leaves  the  spleen  by  the  splenic  vein  contains  a  larger 
number  of  leucocytes  than  the  blood  that  enters  by  the  splenic 
arterv. 


Chap.  XVI] 


SUMMARY 


319 


(2)  The  formation  of  red  corpuscles  during  foetal  life  and  for  a 
short  period  after  birth. 

(3)  The  presence  of  a  large  amount  of  iron  suggests  that  it  may 
help  in  the  preparation  of  new  haemoglobin,  or  in  the  preservation 
of  the  iron  set  free  by  the  death  of  the  red  corpuscles.  The  pres- 
ence of  iron  was  formerly  considered  an  evidence  that  the  red  cor- 
puscles were  destroyed  in  the  spleen,  but  this  is  not  accepted  at 
the  present  time. 

(4)  The  spleen  increases  in  size  during  digestion,  and  after  diges- 
tion is  over  it  returns  to  its  usual  size.  It  is  always  large  in  well- 
fed,  and  small  in  starved  animals.  This  supports  the  belief  that  it 
may  be  concerned  in  digestion  or  metabolism. 

(5)  It  is  probable  that  the  spleen  is  concerned  in  the  production 
of  uric  acid.  Various  waste  products  that  result  from  the  metab- 
olism of  protein  are  found  in  the  spleen,  and  it  is  thought  that  by 
the  action  of  special  enzymes  these  substances  are  changed  to  uric 
acid. 

(6)  In  certain  diseases,  more  especially  typhoid  and  malaria, 
a  temporary  enlargement  takes  place.  Some  physiologists  inter- 
pret this  as  an  evidence  that  the  spleen  has  an  important  protective 
function.  Phagocytosis  is  a  normal  occurrence,  and  in  addition 
it  serves  as  a  filter  and  may  modify  abnormal  material  found  in 
the  blood. 


Metabolism 


SUMMARY 

■  Refers  to  changes  that  occur  in  food-stuffs  from  time  of 
absorption  to  elimination. 

1.  Conversion  of  non-living  material  into 
protoplasm. 

2.  Oxidation. 

3.  Neutralization  or  elimination  of  acids. 

4.  Conversion  of  glucose  into  glycogen  and 
glycogen  into  glucose. 

Anabolic  or  constructive  changes. 
Katabolic  or  destructive  changes. 

1.  Release  of  chemical  energy  in  the  form 
of  heat,  nervous  and  muscular  activity. 

2.  Repair  and  growth  of  tissue, 
r  Enzymes. 
I  Oxygen. 
I  Internal  secretions. 


Consists  of  { 


Equals  the 
sum  of  the 

Functions 

Dependent 
upon 


320 


ANATOMY  FOR  NURSES         [Chap.  XVI 


Metabolism 
of  Fats 


Metabolism  of 
Carbohydrates 


Metabolism 
of  Proteins 


Fats  arc  oxidized   and 
serve  as  fuel 


Function 


Obesity 


Liberation  of  energy. 

I  Carbon 
dioxide. 
Water. 
■  Yield  heat  and  energy. 
Fomi  reserve  fund  for  time  of  need  (adi- 
pose tissue). 
.  Protect  protein  tissue. 
Due  to  excessive  amounts  of  carbohydrates 

and  fats. 
Sedentary  life   and   absence  of  worry  are 
contributing  factors. 


Functions    . 


Conversion  of  simple  sugars  into  glycogen. 
Dependent  f  Control  of  nervous  system, 
upon         I  Action  of  enzjuies. 

Furni.sh  main  source  of  energy  for  mus- 
cular work  and  all  the  nutritive  processes. 
Help  to  maintain  the  body  temperature. 
Form    reserve    fund    for    time    of    need 

(glycogen). 
Protect  the  body  tissues. 
Excess  carbohydrates  are  converted  into 
adipose  tissue. 
Waste  f  Carbon  dioxide. 

Products  I  Water. 

1 .  Conversion  of  peptones,  polypeptids,  and  amino-acida 

into  serum-albumin  and  serum-globulin,  and  the 
conversion  of  these  blood  proteins  into  Uving  tissues. 

2.  Excess  protein  molecules  are  split  into  two  parts. 

One  part  is  converted  into  urea  and  excreted,  the 
other  part  may  be  oxidized  directly,  or  built  into 
carbohydrates  and  fats  and  oxidized  later. 

Adequate  proteins  contain  all  the  materials 

for  maintenance  and  growth  of  tissue. 
Inadequate  proteins  ser\'e  same  purpose  as 
carbohydrates  and  fats. 

1.  Build  up  tissue. 

2.  Serve   same   purpose   as   carbohydrates 
and  fats. 

Nitrogen  equilibrium.  —  Condition  when  the  amount  of 
protein  nitrogen  taken  into  the  body  in  food  is  equal 
to  the  amount  eliminated  in  the  excreta. 


Classifica 
tion 


Function 


Chap.  XVI] 


SUMMARY 


321 


Heat  Value 
of  Food 


Average 
Amount 
of  Food 
required 


Ductless 
Glands 


Thyroid 


Overeating  < 


Heat  results  from  processes  of  oxidation. 

f  Unit  of  measurement  for  heat  production. 

Small  calorie  =  quantity  of  heat  necessary 
I      to  raise  one  gram  of  water  one  degree 
Calorie         •;      centigrade. 

Large  calorie  =  quantity  of  heat  necessary 
to  raise  one  gram  of  water  1000  degrees 
centigrade. 

Fat  —  1  gram  yields  about  9.3  large  calories. 
Carbohydrates  — •  1  gram  yields  about  4.1  large  calories. 
Protein —  1  gram  yields  about  4.1  large  calories. 

r  1.  Activity.  2.  Age. 

Dependent  <  3.  Size.  4.  Sex. 

upon  [  5.  Climate. 

Average       r  Fats  1^  to  |  or  about  930  calories, 
number     I  Carbohydrates  f  to  f  or  about  984  calories, 
of  calories  [  Proteins  ^  or  about  410  calories. 
Undernutrition  —  lessens  natural  powers  of  resistance  to 
disease. 

1.  Puts  unnecessary  strain  on  the  organs  of 
nutrition  and  excretion. 

2.  Favors  obesi'ty. 

3.  Increases    amount    of    waste   products, 
toxic  material,  and  flatulence. 

,  4.  Retards  secretion  of  gastric  juice. 

Glandular  structures  that  possess  no  ducts. 

Produce  internal  secretions  that  are  carried   from  the 

gland  by  the  blood  or  lymph. 
Function  is  imperfectly  understood,  because  it  is  de- 
pendent upon  the  internal  secretions  and  these  cannot 
be  obtained  in  a  pure  state. 
The  Thyroid. 
The  Parathyroids. 
The  Thjonus. 
Most  im-     I  The  Adrenals. 
portant     ]  The  Hypophysis. 
The  Epiphysis. 
The  Carotid  glands. 
.  The  Coccygeal  gland. 

Small  gland.     Weighs  about  one  ounce. 
Consists  of  two  lobes  connected  by  an  isthmus. 
Placed  in  front  of  trachea,  below  thyroid  cartilage. 
Function  not  definitely  known,  but  the  internal  secretion 

is  thought  to  be  necessary  for  normal  growth,  and  the 

functioning  of  all  the  tissues. 


322 


ANATOMY   FOR  NURSES 


[Chap.  XVI 


Parathyroids 


Thymus 


Adrenals   . 


Hypophysis 


Epiphysis  . 


Carotid 
Glands 

Coccygeal 
Gland 


Four  snijiU  ninsscs,  each  about  j  in.  diameter. 
Two  are  emlx'ddcd  in  each  lobe  of  thyroid. 
Consi.st  of  epitlieUoid  cells,  invested  with  areolar  tissue. 
Function  is  supposed  to  consist  in  neutraUzing  toxic 
substance.s. 

Consists  of  two  large  masses  of  glandular  tissue  situated 
below  the  thyroid  and  in  front  of  the  trachea. 

Temporary  organ.  Appears  at  second  month  of  intra- 
uterine life,  grows  until  child  is  two  or  three  years  of 
age,  and  it  weighs  about  six  drachms.  Then  atrophies 
steadily  until  age  of  puberty,  when  onlj^  some  shreds 
of  tissue  are  left. 

Function  not  definitely  known,  but  it  is  thought  to  have 
a  definite  connection  with  growth  and  with  the  de- 
velopment of  the  reproductive  organs. 

Small   glands   lying   above   each   kidney.     Weigh   one 

drachm. 
Consist  of  a  fibrous  framework,  the  spaces  of  which  are 

filled  with  groups  of  cells.     Thej''  are  enclosed  in  a 

fibrous  capsule  and  are  well  supplied  with  blood-vessels, 

lymphatics,  and  nerves. 
Internal  secretion  —  adrenalin. 
Function  seems  to  be  connected  with  maintaining  the 

normal  tone  of  the  heart  and  blood-vessels. 

■  Small  reddish  gray  gland,  weighs  5-10  grains. 

Consists       (  Anterior  lobe,  large  and  glandular. 

of  two      <  Posterior  lobe,  small  and  composed  of  nerve 
lobes    .     [     tissue. 

Lodged  in  depression  of  the  sphenoid  bone. 

Function  not  positively  known,  but  it  is  thought  to  have 
a  definite  connection  with  growth,  with  the  organs  of 
circulation,  with  the  secretion  of  urine  and  milk;  and 
with  the  metaboUsm  of  the  carbohydrates. 

Small  reddish  gray  body  located  in  the  third  ventricle  of 
the  brain.  Glandular  organ  and  attains  maximum 
growth  about  seventh  year.  From  this  period  and 
particularly  after  puberty  it  decreases  in  size  and  be- 
comes fibrous. 

Function  not  definitely  known,  but  it  is  thought  to  in- 
hibit growth  and  restrain  the  development  of  the  re- 
productive organs. 

Small  glands,  one  situated  in  bifurcation  of  each  carotid 

artery. 
Small  gland  A  in.  in  diameter,  situated  in  front  of  tip 

of  coccyx. 


Chap.  XVI] 


SUMMARY 


323 


Descrip- 
tion 


Spleen . 


Functions 


Beneath  diaphragm,  behind  and  to  the  left 

of  the  stomach. 
Consists  of  a  fibrous  network  filled  with  a 

vascular  pulp,  enclosed  in  a  fibrous  and 

muscular  capsule  which  is  covered  by 

serous  membrane. 
Blood  supply  peculiar  —  arteries  —  veins, 

no  connecting  capillaries. 
'  Not  definitely  known.     Credited  with  the 

following :  — 

1.  Formation  of  leucocytes. 

2.  Formation  of  red  corpuscles  during  foetal 

Ufe  and  for  short  period  after  birth. 

3.  Helps    in   preparation    of   new   haemo- 

globin or  preservation  of  iron  set  free 
by  death  of  red  corpuscles. 

4.  May  assist  in  digestion  and  metabolism. 

5.  May  assist  in  production  of  uric  acid. 

6.  May  protect  body  from  infections. 


CHAPTER   XVII 

WASTE  PRODUCTS.  EXCRETORY  ORGANS;  DESCRIPTION  OF  THE 
ORGANS  CONSTITUTING  THE  URINARY  SYSTEM;  GENERAL 
CHARACTERS  OF  URINE;    COMPOSITION  OF  URINE 

In  the  previous  chapters  we  have  seen  that  tlie  blood  is  con- 
stantly supplied  by  means  of  the  respiratory  and  digestive  mechan- 
isms, with  all  the  chemical  substances  it  requires  to  maintain  the 
life,  growth,  and  activity  of  the  body.  These  substances,  entering 
the  current  of  the  blood,  are  carried  to  all  the  tissues,  and  are  in- 
cessantly combining  with  the  chemical  substances  of  which  these 
tissues  are  composed.  One  of  the  results  of  these  chemical  com- 
binations is  the  formation  of  waste  products,  which  must  be  re- 
moved from  the  body,  as  many  of  them  are  toxic. 

WASTE  PRODUCTS 

The  principal  waste  products  formed  in  the  body  are  urea,  uric 
acid,  creatinin,  hippuric  acid,  carbon  dioxide,  and  other  organic 
substances  ;  inorganic  salts  and  water.  Waste  products  are  classed 
as  excreta  and  the  process  by  which  they  are  removed  from  the 
body  as  excretion  or  elimination. 

EXCRETORY  ORGANS 

The  organs  whose  sole  function  is  the  elimination  of  waste 
products  are  the  organs  of  the  urinary  system.  These  are  called 
the  excretory  organs  and  consist  of  the  following  :  — 

2  Kidneys,  which  form  the  urine  from  materials  taken  from  the 

blood. 
2  Ureters,  ducts  which  convey  the  urine  away  from  the  kidneys. 
1  Bladder,  a  reservoir  for  the  reception  of  urine.     (See  Fig.  120.) 
1  Urethra,   a  tube  through  which  the  urine  passes  from  the 

bladder  and  is  finally  voided. 
Other  organs  that  assist  in  the  process  of  elimination  are :  (1)  the 
lungs,  (2)  the  skin,  (3)  the  liver,  and  (4)  the  intestines. 

324 


Chap.  XVII] 


URINARY  SYSTEM 


325 


The  waste  matters 
lungs,  skin,  liver,  and 
(1)  By  the  urinary 
organs : 


(2)  By  the  lungs 


(3)  By  the  skin : 


(4)  By  the  liver : 


(5)  By  the  intes- 
tines : 


discharged  relatively  by  the  urinary  organs, 

intestines  may  be  stated  as  follows  :  — 

All,  or  nearly  all,  the  urea  and  allied  bodies.^ 
These  waste  products  result  from  the  me- 
tabolism of  food  proteins  and  body  tissues. 

The  greater  portion  of  the  salts.  These 
salts  represent  those  taken  into  the  body 
and  not  utilized,  also  those  that  result 
from  the  neutralization  of  acids  and  the 
metabolism  of  foods  and  tissues. 

A  large  amount  of  water.  This  consists  of 
water  taken  as  such  with  food,  and  that 
formed  in  the  body  as  the  result  of  chem- 
ical reactions. 

A  very  small  quantity  of  carbon  dioxide. 

The  greater  part  of  the  carbon  dioxide, 
formed  by  oxidation. 

A  considerable  quantity  of  water. 

A  small  quantity  of  urea  is  eliminated  in 
diseased  conditions  of  the  kidneys. 

A  variable  but,  on  the  whole,  large  quantity 
of  water.  This  is  influenced  by  temper- 
ature, and  the  amount  excreted  by  the 
kidneys. 

A  small  quantity  of  salts. 

A  small  quantity  of  urea.  Under  normal 
conditions  the  quantity  of  urea  is  negli- 
gible, but  in  diseased  conditions  of  the 
kidneys  or  when  free  perspiration  is  in- 
duced, the  quantity  is  increased. 

A  small  quantity  of  carbon  dioxide.' 

A  small  quantity  of  bile.  This  contains 
waste  products  that  result  from  chemical 
reactions  that  occur  in  the  liver. 

Undigested  and  indigestible  food  material. 

A  small  quantity  of  salts. 

In  diseased  conditions  of  the  kidneys,  some 
urea  and  allied  bodies. 


*  Uric  acid,  hippuric  acid,  creatin,  creatinLa,  xanthin,  etc. 


326 


ANATOMY  FOR   NURSES         [Chap.  XVII 


In  this  chapter  we  shall  devote  ourselves  to  the  consideration  of 
the  urinary  system. 

KIDNEYS 

The  kidneys  are  two  compound  tubular  glands,  placed  at  the 
back  of  the  abdominal  cavity,  one  on  each  side  of  the  spinal  column 
and  behind  the  peritoneal  cavity.     They  correspond  in  position 

to  the  space  included  between 
the  upper  border  of  the  twelfth 
thoracic  and  the  third  lumbar 
\ertebra.  The  right  is  a  little 
lower  than  the  left  in  conse- 
(lucnce  of  the  large  space  oc- 
cu])ied  by  the  liver. 

Capsule  and  supports.  —  The 
kidneys  are  covered  by  a  thin 
but  rather  tough  envelope  of 
fibrous  tissue  called  the  capsule 
of  the  kidney,  and  are  usually 
embedded  in  a  considerable 
quantity  of  fat,  which,  with  the 
assistance  of  their  vessels  and 
the  peritoneum,  helps  to  hold 
them  in  place. 

Size  and  shape.  —  Each  kidney 
is  about  four  inches  (100  mm.) 
long,  two  inches  (50  mm.)  broad, 
one  inch  (25  mm.)  thick,  and 
weighs  about  four  and  one  half 
ounces  (135  gm.)  They  are  bean-shaped,  with  the  concave  side 
turned  toward  the  spine,  and  the  convex  side  directed  outward. 
Near  the  centre  of  the  concave  side  is  a  depression  called  the  hilum, 
which  serves  as  a  passageway  for  the  ureter,  and  for  the  blood- 
vessels, lymph-vessels,  and  nerves  going  to  and  from  the  kidney. 
Anatomy  of  the  kidney.  —  If  we  cut  a  kidney  in  two  lengthwise, 
it  is  seen  that  the  upper  end  of  the  ureter  expands  into  a  basin-like 
cavity,  called  the  pelvis  of  the  kidney.  This  pelvis  is  irregularly 
subdivided  into  smaller,  cup-like  cavities,  called  calyces,  which 
receive  the  pointed  projections  of  the  kidney  substance. 


Fig.  IGG.  —  Vertical  Section  of  the 
Kidney.     (Collins.) 


Chap.  XVII]  URINARY  SYSTEM  327 

The  substance  of  the  kithiey  is  readily  seen  by  the  naked  eye 
to  consist  of  two  distinct  parts:  (1)  An  outer,  Hghter,  and  more 
soHd  portion,  called  the  cortex  (bark).  (2)  An  inner,  darker, 
striated  portion,  called  the  medulla  (marrow),  which  is  not  a  solid 
mass,  but  more  or  less  distinctly  divided  into  pyramidal-shaped  sec- 
tions. The  pointed  projections,  or  papillae,  of  the  pyramids  are  re- 
ceived by  the  cup-like  cavities  or  calyces  of  the  pelvis.  The  bulk 
of  the  kidney  substance,  both  in  the  cortex  and  medulla,  is  com- 
posed of  little  tubes  or  tubules,  closely  packed  together,  having  only 
just  so  much  connective  tissue  as  is  sufficient  to  carry  a  large  supply 
of  lilood-vessels  and  a  certain  number  of  lymphatics  and  nerves. 

Urinif erous  tubules.  —  Examined  under  the  microscope,  it  is 
seen  that  the  uriniferous  tubules  begin  as  little  hollow  globes,  called 
capsules,  in  the  cortex  of  the  kidney.  These  capsules  are  joined 
to  the  tubules  by  a  constricted  neck,  and  the  tubules,  after  running 
a  very  irregular  course,  open  into  straight  collecting  tubes,  which 
pour  their  contents  through  their  openings  in  the  pointed  ends  or 
papillte  of  the  pyramids,  into  the  calyces  of  the  kidney. 

The  tubules  are  composed  of  basement  membrane,  lined  through- 
out by  epithelial  cells.  The  cells  vary  in  the  different  parts  of  a 
tubule,  those  of  the  capsule  and  convoluted  or  irregular  parts  being 
more  especially  adapted  to  secretory  purposes  than  the  straight 
parts  of  the  tubule. 

Pyramid.  —  These  collecting  tubules  en  masse,  together  with 
interstitial  tissue,  blood-vessels,  and  lymphatics,  make  a  pyramid. 
The  number  of  pyramids  varies  from  eight  to  twelve. 

Renal  or  Malpighian  corpuscles.  —  In  the  cortical  portion  of  the 
kidney  are  found  renal  corpuscles  which  consist  of  two  parts  :  (1)  a 
minute  tuft  of  capillaries  called  a  glomerulus,  surrounded  by  (2)  a 
closed  capsule  which  is  the  beginning  of  a  uriniferous  tubule. 
The  investment  of  the  glomerulus  by  the  capsule  is  double  and 
quite  complete  except  at  one  point  where  an  afferent  vessel  enters, 
and  an  efferent  vessel  leaves. 

The  blood  supply  of  the  kidney.  —  For  its  size,  the  kidney  is 
abundantly  supplied  with  blood.  The  renal  artery,  coming  di- 
rectly from  the  aorta,  divides,  before  it  enters  the  hilus  of  the  kid- 
ney, into  several  branches,  which  pass  into  the  tissue  of  the  organ. 
Branches  from  these  arteries  have  two  destinations :  (1)  into 
the  cortex,  and  (2)  into  the  pyramids. 


Fig.  167.  —  Diagram  of  the  STnucTURE  of  a  Lobe  of  the  Kidney.  The  lobe 
is  seen  in  vertical  section,  the  cortex  being  marked  off  from  the  medulla.  Four 
medullary  rays  encroach  upon  the  cortex.  At  the  left  is  shown  the  course  of  a  single, 
continuous  series  of  tubes  —  the  straight  and  spiral  tubes  appearing  in  the  medul- 
lary ray,  the  straight,  looped,  and  excretory  in  the  medulla  proper,  the  capsule, 
neck,  convoluted,  irregular,  and  arched  in  the  cortex  proper.  Next  is  seen  the 
lab>Tinth,  composed  of  a  mass  of  tubes  in  the  cortex,  with  a  medullary  ray  for  a 
centre.  Equidistant  from  the  ray  on  each  side  is  a  broken  red  line,  marking  the 
position  of  an  interlobular  artery.  The  parts  between  these  lines  constitute  a 
lobule.  Farther  to  the  right  is  an  interlobular  artery,  gi%'ing  off  lateral  branches 
(afferent  vessels),  each  of  which  ends  in  a  tuft  of  capillaries,  from  which  the 
blood  is  collected  by  an  efferent  vessel.  The  uppermost  of  the  tufts  is  showti 
enclosed  in  a  capsule.  On  the  right  of  the  interlobular  artery  the  efferent  vessels 
break  up  into  a  capillary  network  which  surrounds  the  (unrepresented)  tubes  in  the 
cortex  and  ray.  The  lowest  efferent  sends  vertical  vessels  also  into  the  medulla. 
On  the  right  the  interlobular  vein  is  seen  gathering  the  blood  from  all  the  parts  sup- 
plied by  the  interlobular  artery.  A  branch  of  the  renal  artery  courses  upward  be- 
tween cortex  and  medulla,  and  forms  an  arch  (here  broken)  over  the  base  of  the 
medulla.  From  it  the  inttrlol)\ilar  arteries  pass  upward  into  the  cortex,  and 
straight  branches  go  downward  into  the  medulla,  suppljing  its  structure,  and  end- 
ing at  the  apex  in  the  capillaries.  From  the  last  the  radicles  of  the  renal  vein 
arise,  and  accompany  the  straight  arteries  to  the  base  of  the  medulla,  where  a  %'e- 
nous  arch  is  formed,  continuous  with  which  is  the  vena  comes  of  the  entering  artery. 
The  caljTC  embraces  the  apex  of  the  medullary  pyramid.  It  is  lined  with  epithe- 
lium, which  continues  from  it  ov^er  the  apex,  the  latter  being  perforated  with  the 
many  apertures  of  excretory  tubes.     (Gerrish.) 

328 


Chap.  XVII] 


URINARY  SYSTEM 


329 


(1)  When  the  arteries  reach  the  level  of  the  base  of  the  pyra- 
mid, the  branches  divide  laterally  to  form  more  or  less  com- 
plete arches  between  the  cortex  and  medulla.  From  the  arterial 
arches,  vessels  pass  upward  through  the  cortex  (interlobular), 
giving  off  at  intervals  tiny  arteries,  each  of  which  enters  the 
dilated  commencement  or  capsule  of  a  uriniferous  tubule.  These 
tiny  arteries,  entering  the  capsule,  are  spoken  of  as  afferent  vessels. 
They  push  the  thin  walls  of  the  capsule  before  them,  break  up  into 
a  knot  of  capillary  vessels,  called  a  glomer- 
ulus, and  finally  issue  from  the  capsule  as 
efferent  vessels,  near  the  point  at  which  the 
afferent  vessel  entered.  These  efferent  ves- 
sels are  much  smaller  than  the  afferent  ves- 
sels. They  do  not  immediately  join  to  form 
veins,  but  break  up  into  a  close  meshwork 
or  plexus  of  capillaries  around  the  tubules, 
before  they  unite  to  form  the  larger  vessels 
and  pour  their  contents  into  the  veins. 
These  veins  terminate  in  venous  arches  be- 
tween the  cortex  and  medulla.  It  is  in  this 
way  that  the  cortex  is  supplied  with  blood. 

(2)  The  pyramids  also  receive  their 
blood  supply  from  the  arterial  arches.  The 
blood  passes  downward  in  straight  vessels 
between  the  uriniferous  tubules,  to  be  re- 
turned by  more  or  less  straight  veins  to  the 

venous  arches,  whence  it  is  conveyed  by  large  branches  into  the 
renal  vein,  which  leaves  the  kidney  at  the  hilus  and  pours  its 
contents  into  the  inferior  vena  cava. 

It  is  worthy  of  note  that,  unlike  the  lungs  and  the  liver,  the 
kidney  receives  blood  from  just  one  artery,  and  this  blood  distrib- 
uted in  different  sets  of  vessels  serves  the  purposes  of  nourish- 
ment for  the  kidney  substance,  and  the  purposes  of  excretion.  It 
is  from  the  capillaries  of  the  glomeruli  and  the  plexus  of  capillaries 
around  the  convoluted  portion  of  the  tubules,  that  the  passage  of 
waste  material  from  the  blood  into  the  tubule  takes  place.  Other 
capillaries  serve  to  hold  the  blood  that  is  used  for  nourishment. 

Nerves  and  lymphatics.  —  The  kidneys  are  well  supplied  with 
nerves  derived  from  both  the  sympathetic  and  central  nervous 


Fig.  168.  —  Plan  of 
THE  Blood-vessels  con- 
nected WITH  THE  Tu- 
bules. (Note  that  in  the 
text  the  term  "renal  or 
Malpighian  corpuscles"  is 
ussd  instead  of  the  term 
' '  Malpighian  body  "  which 
is  found  on  the  illustra- 
tion.) 


330  ANATOMY   FOR  NURSES         [Chap.  XVII 

system.  Many  of  these  nerves  are  vasomotor  nerves,  and  by  regu- 
lating the  contraction  and  relaxation  of  the  blood-vessels,  they  in- 
fluence the  blood  pressure  in  the  kidney.  They  are  also  well  sup- 
plied with  lymphatics. 

Function  of  the  kidneys.  —  The  function  of  the  kidneys  is  to 
separate  waste  matters  (urine)  from  the  blood,  and  thus  help  to 
maintain  the  normal  composition  of  the  blood.  The  waste  matters 
are  those  resulting  from  metabolism,  particularly  of  proteins, 
water,  salts,  and  foreign  matters  such  as  toxins,  whether  formed 
in  the  body,  or  taken  into  the  body  from  outside. 

The  secretion  of  urine.  —  The  exact  way  in  which  the  kidneys 
separate  the  urine  from  the  blood  is  not  known,  but  it  is  thought 
to  be  a  double  process,  being  partially  accomplished  by  transuda- 
tion, and  partially  by  the  selective  action  of  the  secreting  cells 
lining  the  tubules. 

(1)  Into  each  hollow  capsule  which  forms  the  beginning  of  a 
uriniferous  tubule  an  afferent  artery  enters.  This  artery  breaks 
up  into  capillaries  which  form  a  bunch  of  looped  and  twisted 
blood-vessels  called  a  glomerulus.  The  walls  of  the  capsule  being 
double,  the  glomerulus  pushes  back  the  inner  wall  or  visceral 
layer,  until  the  capsule  is  entirely  filled,  leaving  only  a  small  space 
between  it  and  the  outer  wall  or  parietal  layer.  The  blood  in  the 
glomerulus  is  only  separated  from  the  interior  of  the  tubule  by 
the  thin  walls  of  the  capillaries  and  the  inverted  wall  of  the 
capsule.  The  artery  (afferent)  which  enters  the  capsule  is  larger 
than  the  issuing  (efferent)  vessel,  and  during  its  passage  through 
the  glomerulus,  the  blood  is  subjected  to  considerable  pressure. 
As  a  result  of  this,  a  transudation  of  the  watery  constituents  of 
the  blood,  with  some  dissolved  salts,  takes  place  through  the 
walls  of  the  blood-vessels  and  the  walls  of  the  capsule  into  the 
capsular  space,  then  into  the  tubule. 

(2)  After  leaving  the  capsule,  the  efferent  vessel  communicates 
with  other  similar  vessels,  which  together  form  a  meshwork  or 
plexus  of  capillaries  closely  surrounding  the  tubules,  so  that  the 
blood  is  again  brought  into  close  communication  with  the  in- 
terior of  the  tubules.  The  tubules  are  lined  with  secreting  cells, 
and  these  cells  appear  to  have  the  power  of  selecting  from  the 
blood  the  more  solid  waste  matters  (especially  the  urea),  which 
fail  to  filter  through  the  flat  cells  forming  the  wall  of  the  capsule. 


Chap.  XVII] 


URINARY  SYSTEM 


331 


Fig.  169.  —  Diagram  show- 
ing Method  of  Entrance  of 
THE  Ureter  into  the  Bladder. 
(Gerrish.) 


THE  URETERS 

The  ureters  are  the  excretory  ducts  of  the  kidneys.  They  con- 
sist of  a  distended  portion  called  the  pelvis,  which  is  contained 
within  the  kidney,  and  a  duct.  Each  duct  is  about  the  diameter 
of  a  goose-quill,  and  from  twelve  to  eighteen  inches  (300  to 
450  mm.)  long.  They  consist  of  three 
coats :  — 

(1)  An  inner  or  mucous  coat  con- 
tinuous above  with  that  of  the  pelvis 
of  the  kidney,  and  below  with  that 
of  the  bladder. 

(2)  A  middle  or  muscular  coat 
which  is  arranged  in  two  layers,  an 
inner  longitudinal,  and  an  outer  cir- 
cular. 

(3)  An  outer  or  fibrous  coat  which 
carries  the  blood-vessels  and  nerves 
with  which  the  tube  is  supplied. 

Function.  —  The  ureters  connect  the  kidneys  with  the  bladder 
and  serve  as  a  passageway  to  convey  urine  from  the  kidneys  to 
the  bladder. 

BLADDER 

The  bladder  is  a  hollow  muscular  organ  situated  in  the  pelvic 
cavity  behind  the  pubes,  in  front  of  the  rectum  in  the  male,  and  in 
front  of  the  anterior  wall  of  the  vagina,  and  the  neck  of  the  uterus, 
in  the  female.  It  is  a  freely  movable  organ,  but  is  held  in  position 
by  ligaments.  During  infancy  it  is  conical  in  shape  and  projects 
above  the  upper  border  of  the  pubes  into  the  hypogastric  region. 
In  the  adult,  when  quite  empty,  it  is  placed  deeply  in  the  pelvis ; 
when  slightly  distended,  it  has  a  round  form ;  but  when  greatly 
distended,  it  is  ovoid  in  shape  and  rises  to  a  considerable 
height  in  the  abdominal  cavity.  It  is  customary  to  speak  of  the 
widest  part  as  the  fundus,  and  the  part  where  the  bladder  becomes 
continuous  with  the  urethra  as  the  neck,  or  cervix.  It  has  four 
coats : — 

1.  The  mucous  membrane  lining  the  bladder  is  continuous 
with  that  of  the  ureters  and  the  urethra.  When  the  bladder 
is  empty,  the  mucous  membrane  is  thrown  into  irregular  rugae. 


332  ANATOMY   FOR  NURSES         [Chap.  XVll 

2.  The  areolar  coat  connects  the  mucous  and  muscular.  It 
permits  freedom  of  movement  such  as  is  essential  in  an  organ 
subject  to  change  in  size  and  shape. 

3.  The  muscular  coat  has  three  layers,  an  inner  longitudinal, 
middle  circular,  and  outer  longitudinal.  The  circular  fibres  are 
collected  into  a  layer  of  some  thickness  around  the  cervix  or 
neck,  where  the  bladder  becomes  continuous  with  the  urethra. 
These  circular  fibres  around  the  neck  form  a  sphincter  muscle 
which  is  normally  in  a  state  of  contraction,  only  relaxing  at 
intervals,  when  the  accumulation  of  urine  within  the  bladder 
renders  its  expulsion  necessary. 

4.  The  serous  coat  is  a  reflection  of  the  peritoneum,  and  only 
covers  the  upper  portion  of  the  fundus. 

Function.  —  The  bladder  serves  as  a  reservoir  for  the  reception 
of  urine.  When  moderately  distended,  it  holds  about  one  pint 
(about  one-half  litre). 

THE  URETHRA 

The  urethra  is  a  narrow,  membranous  canal,  about  an  inch 
and  a  half  (38  mm.)  in  length  in  the  female.  Its  normal  diameter 
is  about  one-quarter  of  an  inch  (6.3  mm.),  but  it  admits  of  consid- 
erable dilatation.  It  extends  from  the  neck  of  the  bladder  to  the 
external  orifice,  which  is  named  the  meatus  urinarius.  It  is  placed 
behind  the  symphysis  pubis,  and  is  embedded  in  the  anterior  wall 
of  the  vagina.  Its  direction  is  obliquely  downward  and  forward, 
its  course  being  slightly  curved,  with  the  concavity  directed  for- 
ward and  upward.  Its  external  orifice  is  the  narrowest  part  and 
is  located  between  the  clitoris  and  the  opening  of  the  vagina.  (See 
Fig.  207.) 

The  wall  of  the  urethra  consists  of  three  coats :  — 

(1)  An  inner  or  mucous  coat  which  is  continuous  with  that  of 
the  bladder. 

(2)  A  submucous  coat  which  contains  a  network  of  veins. 

(3)  An  outer  muscular  coat  which  is  continuous  with  that  of  the 
bladder. 

MICTURITION 

Urine  is  secreted  continuously  by  the  kidneys.  It  is  carried 
to  the  bladder  by  the  ureters,  and  at  intervals  is  expelled  from  the 


Chap.  XVII]  URINARY   SYSTEM  333 

bladder  through  the  urethra.  The  act  by  which  the  urine  is  ex- 
pelled is  called  micturition.  It  occurs  normally  as  the  result  of 
irritation  due  to  the  accumulation  of  urine  within  the  bladder. 
The  accumulation  stimulates  the  muscular  walls  to  contract,  and 
the  resistance  of  the  sphincter  at  the  neck  of  the  bladder  is  over- 
come. The  action  is  involuntary,  but  it  may  be  controlled  by  vol- 
untary effort. 

Involuntary  micturition.  —  Involuntary  micturition  may  occui 
as  the  result  of  lack  of  consciousness ;  and  as  the  result  of  spinal 
injury  involving  the  nerve  centres,  which  send  nerves  of  control 
to  the  bladder.  It  may  be  due  to  a  want  of  "  tone  "  in  the  muscu- 
lar walls,  or  it  may  result  from  some  abnormal  irritation. 

Retention  of  urine.  —  When  the  kidneys  secrete  urine,  but  it  is 
retained  within  the  bladder,  we  speak  of  it  as  retention.  Reten- 
tion or  failure  to  void  urine  may  be  due  to :  (1)  dulling  of  the 
senses  so  that  there  is  no  desire  to  void,  (2)  nervous  contraction  of 
the  urethra,  and  (3)  some  obstruction  in  the  urethra  or  in  the 
neck  of  the  bladder. 

In  some  cases  the  bladder  may  become  so  fully  distended  that 
the  retention  of  urine  may  be  accompanied  by  more  or  less  con- 
stant voiding  of  small  amounts  of  urine. 

Suppression  of  iirine.  —  When  the  kidneys  fail  to  secrete  urine, 
it  is  spoken  of  as  suppression,  and  is  a  far  more  serious  condition 
than  retention,  as  it  is  usually  due  to  disease  of  the  kidneys. 

GENERAL  CHARACTERS  OF  THE  URINE 

Normal  urine  may  be  described  as  a  transparent,  amber-colored 
liquid,  with  a  characteristic  odor,  an  acid  reaction,  and  a  specific 
gravity  of  about  1.020. 

Transparency.  —  The  transparency  of  urine  may  be  diminished 
in  health  by  the  presence  of  mucus,  derived  from  the  genito- 
urinary tract,  or  by  the  deposit  of  salts.  In  disease  the  urine  may 
become  clouded  by  the  presence  of  pus. 

Color.  —  The  color  of  urine  depends  upon  the  quantity  voided 
and  the  relative  amounts  of  water  and  coloring  matters.  If  the 
quantity  is  abnormally  increased,  it  is  usually  more  dilute  and  of 
a  paler  color;  as,  for  instance,  the  copious  light-colored  urine  of 
hysteria  or  diabetes  insipidus.  One  exception  to  this  is  diabetes 
mellitus,  where  the  quantity  is  increased,  but  the  color  is  dark 


334  ANATOMY  FOR   NURSES  [Chap.  XVII 

because  of  the  presence  of  sugar.  When  the  quantity  is  diminished, 
as  in  fevers,  it  is  generally  highly  colored,  because  the  amount  of 
solids  present  is  large.  Other  causes  of  change  of  color  are  the 
presence  of  abnormal  substances,  and  large  doses  of  certain  drugs. 

Reaction.  —  The  reaction  of  human  urine  is  largely  dependent 
on  the  kind  of  food  we  eat.  Many  of  the  waste  products  that 
result  from  a  mixed  diet  are  acid,  hence  the  reaction  of  human  urine 
is  usually  acid.  On  a  diet  of  carbohydrates  the  urine  will  be  alka- 
line, as  it  is  with  herbivorous  animals.  If  human  urine  is  allowed 
to  stand  for  any  length  of  time,  it  will  become  alkaline,  because 
bacteria  will  decompose  the  protein  constituents  into  ammonia 
and  other  alkalies.  In  certain  diseased  conditions  of  the  urinary 
organs  this  same  process  takes  place  within  the  body. 

Specific  gravity.  —  The  specific  gravity  depends  upon  the 
amount  of  solid  waste  matters  present  in  the  urine.  In  health, 
it  may  vary  from  1.010  to  1.030.  When  the  solids  are  dissolved 
in  a  large  amount  of  water,  the  specific  gravity  will  naturally  be 
lower  than  when,  from  a  deficiency  of  water,  the  urine  is  more 
concentrated.  A  high  specific  gravity  denotes  the  presence  of 
abnormal  constituents ;  as,  for  instance,  the  specific  gravity  is  not- 
ably heightened  by  the  presence  of  sugar  in  diabetes  mellitus. 
A  low  specific  gravity  generally  denotes  the  presence  of  albumin, 
or  hysteria  or  mere  polyuria. 

Quantity.  —  The  average  quantity  of  urine  secreted  in  twenty- 
four  hours  by  a  healthy  adult  is  from  forty  to  fifty  ounces  (1.19 
to  1.48  litres).  A  child  voids  relatively  more  urine  than  an  adult, 
but  absolutely  it  voids  less. 

From  2-5  years,  16-24  ounces. 
'  From  5-8  years,  24-32  ounces. 
From  9-16  years,  32-40  ounces. 

The  quantity  of  urine  may  be  increased  by  (1)  the  ingestion  of 
a  large  amount  of  liquids,  (2)  the  action  of  diuretics,  (3)  nervous- 
ness, (4)  certain  diseases  such  as  diabetes  insipidus,  diabetes 
mellitus,  and  hysteria. 

The  quantity  of  urine  may  be  decreased  by  (1)  the  ingestion  of 
a  small  amount  of  liquids,  (2)  vomiting,  (3)  diarrhoea,  (4)  high 
fever,  (5)  disease  of  the  kidneys,  and  (6)  the  action  of  diapho- 
retics, muscular  activity,  or  any  treatment  that  induces  free  per- 
spiration. 


Chap.  XVII] 


URINARY  SYSTEM 


335 


COMPOSITION   OF  URINE 

The  composition  of  urine  is  very  complex;  even  in  health  it 
varies,  depending  on  the  quantity  and  kind  of  food  eaten,  etc. 
The  chief  constituents  are  as  follows :  — 


Urine 


Water, 

95  per  cent 


Solids, 
5  per  cent 


Organic, 
about  3.7 


Inorganic, 
about  1.3 


Urea  (2  per  cent  of  total  solids). 

Uric  acid. 

Creatinin. 

Hippuric  acid. 

Other  substances. 

Sodium  chloride. 

Sulphates. 

Phosphates. 

Potassium. 

Ammonimn. 

Magnesiimi. 

Calcium. 

Other  substances 


,  Salts  of 


Urea.  —  Urea  constitutes  about  one-half  of  the  solid  constitu- 
ents of  the  urine,  and  represents  the  chief  end  product  resulting 
from  the  metabolism  of  the  proteins  of  the  food  and  tissues.  The 
result  of  the  oxidation  of  protein  material  exists  in  the  blood  until 
the  blood  reaches  the  liver.  Under  the  action  of  the  liver  cells 
this  material  (ammonium  carbamate)  is  converted  into  urea  and 
remains  in  the  circulation  until  the  blood  reaches  the  kidneys. 
To  eliminate  urea  is  the  special  work  of  the  kidneys,  and  if  for  any 
reason  they  fail  to  execute  their  work,  the  accumulation  of  urea 
in  the  system  leads  to  a  condition  of  poisoning. 

Normally  an  adult  voids  about  one  ounce  (30  gm.)  in  twenty- 
four  hours,  but  the  quantity  is  increased  by  a  diet  rich  in  proteins, 
strenuous  exercise,  fever,  and  some  diseases.  A  small  amount 
of  protein  food,  excessive  vomiting,  free  perspiration,  and  diseases 
that  interfere  with  elimination  will  decrease  the  amount  of  urea 
voided. 

Uric  acid.  —  Uric  acid  is  thought  to  represent  the  end  products 
resulting  from  the  oxidation  of  the  tissues,  and  next  to  urea  is  the 
medium  by  which  nitrogen  is  eliminated  from  the  body.  Uric 
acid  combines  with  potassium  and  sodium  to  form  urates,  and  is 
found  in  the  form  of  urates  in  the  urine.     In  gout  the  excretion  of 


336  ANATOMY   FOR  NURSES  [Chap.  XVII 

urates  is  decreased,  and  it  accumulates  in  the  blood  and  is  deposited 
in  the  tissues. 

Creatinin.  —  Creatinin  represents  a  meat  extractive  and  may  be 
taken  into  the  body  in  food,  or  formed  in  the  body  by  the  oxida- 
tion of  certain  proteins. 

Hippuric  acid.  —  This  is  increased  in  amount  by  a  vegetable 
diet,  so  that  it  is  thought  to  represent  a  waste  product  that  results 
from  the  metabolism  of  vegetables.  However,  some  hippuric 
acid  is  excreted  even  on  a  meat  diet,  so  that  it  may  result  from  the 
metabolism  of  proteins,  or  it  may  be  derived  from  the  jjrocess  of 
protein  putrefaction  that  occurs  in  the  intestines. 

Salts.  —  The  salts  found  in  the  blood  are  derived  partly  from  the 
food  eaten,  and  partly  from  the  metabolism  of  proteins,  particu- 
larly the  neutralization  of  acids.  Sodium  chloride  is  the  most 
abundant,  and,  next  to  urea,  is  the  chief  solid  found  in  urine.  In 
certain  inflammatory  conditions,  coupled  with  serous  exudate, 
the  amount  of  sodium  chloride  excreted  is  very  much  diminished. 

Abnormal  constituents.  —  The  chief  abnormal  constituents 
that  are  liable  to  appear  in  the  urine  are  albumin,  glucose,  indican, 
acetone,  casts,  calculi,  pus,  and  blood. 

Albumin.  —  Normally  the  kidney  cells  do  not  allow  albumin  to 
pass  into  the  tubules,  but  a  condition  of  temporary  albuminuria 
may  follow  overeating  or  severe  muscular  exercise.  In  abnormal 
conditions  of  the  kidneys  associated  with  nephritis  and  acute 
fevers,  albumin  is  usually  found  in  the  urine.  In  cases  of  heart 
disease,  where  the  blood  vessels  of  the  kidney  are  subjected  to  ab- 
normal pressure  changes,  albumin  is  usually  present  in  the  urine. 

Glucose.  —  In  health  the  amount  of  glucose  present  in  the  blood 
varies  from  0.1  to  0.15  per  cent.  A  higher  per  cent  is  irritating 
to  the  tissues,  so  when  the  quantity  of  sugar  eaten  is  greater  than 
the  system  can  promptly  change  to  glycogen  and  fat,  the  kidneys 
secrete  and  excrete  it.  When  glucose  is  found  in  the  urine  from  this 
cause,  it  is  called  temporary  glycosuria.  Temporary  glycosuria 
frequently  follows  an  injury  to  the  head,  or  occurs  during  convales- 
cence from  fevers.  In  these  cases  it  is  thought  to  be  due  to  tem- 
porary inability  of  the  system  to  oxidize  sugar.  In  the  disease 
called  diabetes  mellitus  glucose  persists  in  the  urine.  In  mild 
cases  this  condition  can  be  controlled  by  lessening  the  amount 
of  carbohydrate  food,  but  in  severe  cases  glucose  will  appear  in  the 


Chap.  XVII]  URINARY  SYSTEM  337 

urine  even  when  no  carbohydrates  are  eaten.  This  condition  is 
serious  because  it  means  that  the  body  tissues  are  being  oxidized 
to  form  glucose.  The  cause  of  diabetes  meUitus  is  not  definitely 
known.  It  frequently  follows  injuries  to  the  head,  and  is  asso- 
ciated with  disease  of  the  pancreas,  which  interferes  with  the  in- 
ternal secretion. 

Indican.  —  Indican  is  a  substance  that  is  formed  from  indol. 
Indol  results  from  the  putrefaction  of  protein  food  in  the  large 
intestine.  It  is  absorbed  and  carried  to  the  liver,  which  it  is 
thought  changes  the  indol  to  indican,  a  less  poisonous  substance. 
Traces  of  indican  are  found  in  normal  urine,  but  the  presence  of  it 
in  any  amount  is  abnormal  and  denotes  :  (1)  excessive  putrefaction 
of  protein  food  in  the  intestines,  or  (2)  disease  of  the  stomach. 

(1)  Excessive  putrefaction  may  be  due  to  a  diseased  condition  of  the 
intestine  that  interferes  with  absorption,  to  a  diet  containing  too 
much  protein  food,  or  to  constipation.  (2)  In  certain  diseases  of 
the  stomach,  food  is  held  until  it  undergoes  fermentative  changes. 

Acetone.  —  Acetone  is  a  volatile  substance  that  is  thought  to 
be  the  result  of  incomplete  oxidation  of  fats  and  possibly  of  pro- 
teins. It  is  found  in  the  urine  of  individuals  suffering  from  defec- 
tive metabolism,  and  in  the  urine  of  normal  individuals  during 
periods  of  fasting. 

Casts.  —  In  some  abnormal  conditions  the  kidney  tubules  be- 
come lined  with  substances  which  harden  and  form  a  mould  or  cast 
inside  the  tube.  Later  these  casts  are  washed  out  by  the  urine, 
and  their  presence  in  urine  can  be  detected  by  the  aid  of  a  micro- 
scope. They  are  named  either  from  the  substances  composing 
them  or  from  their  appearance.     Thus  there  are  (1)  pus  casts, 

(2)  blood  casts,  (3)  epithelial  casts  from  the  walls  of  the  tubes, 
(4)  granular  casts  from  cells  which  have  decomposed  and  form 
masses  of  granules,  (5)  fatty  casts  from  cells  which  have  become 
fatty,  and  (6)  hyaline  casts  which  are  formed  from  coaguiable 
elements  of  the  blood. 

Calculi.  —  A  deposit  of  solid  matter  that  has  been  precipitated 
from  the  urine  is  called  a  urinary  calculus  or  stone.  They  vary  in 
size,  shape,  and  composition,  the  size  and  shape  being  determined 
largely  by  their  composition  and  location.  They  may  be  formed 
in  any  part  of  the  urinary  tract  from  the  tubules  to  the  external 
orifice  of  the  urethra.     The  causes  which  lead  to  their  formation 


338 


ANATOMY  FOR  NURSES         IChap.  XVII 


are  (1)  an  increase  in  the  slightly  soluble  constituents  of  the  urine, 
(2)  a  decrease  in  the  amount  of  water  secreted,  and  (3)  abnor- 
mally acid  or  abnormally  alkaline  urine. 

Pus.  —  In  suppurative  conditions  of  any  of  the  urinary  organs 
pus  cells  are  present  in  the  urine. 

Blood.  —  In  cases  of  acute  inflammation  of  any  of  the  urinary 
organs,  of  tuberculosis,  of  cancer,  and  of  renal  stone,  red  blood 
corpuscles  may  be  found  in  the  urine.  If  present  in  large  numbers, 
they  make  the  urine  look  like  blood,  and  this  condition  is  known 
as  hematuria. 

Toxicity  of  urine.  —  As  urine  is  the  medium  by  which  the  body 
gets  rid  of  toxic  material,  it  follows  that  urine  itself  is  toxic,  and 
must  be  eliminated,  else  a  condition  of  toxemia  will  result.  This 
condition  is  called  uremia,  because  it  was  thought  that  the  symp- 
toms of  poisoning  were  due  to  the  retention  of  urea  in  the  body. 
It  is  now  believed  that  while  urea  is  poisonous,  it  is  only  one  of 
several  substances  that  renders  urine  toxic.  During  illness  the 
kidneys  always  try  to  eliminate  any  poisonous  substances  that  find 
their  way  into  the  blood,  whether  these  substances  are  derived 
from  defective  metabolism  or  from  bacterial  activity.  This  ac- 
counts for  the  fact  that  after  a  severe  illness  the  kidneys  are  often 
left  in  a  damaged  condition. 


Waste  Prod- 
ucts or 
Excreta 


Excretory 
Organs 


SUMMARY 

Urea. 

Uric  acid. 

Creatinin. 

Hippuric  acid. 

Carbon  dioxide. 

Other  organic  substances. 

Inorganic  salts. 

Water. 


Urinary 
system 


Assist  in 
excretion 


Kidneys  (2)  —  secrete  urine. 

Ureters  (2)  —  ducts  which  convey  urine  from 

kidneys  to  bladder. 
Bladder  (1)  —  reservoir  for  urine. 
Urethra  (1)  —  tube  through  which  urine  is 

voided. 
Lungs. 
Skin. 
Liver. 
Intestines. 


Chap.  XVII] 


SUMMARY 


339 


Location 


'  Posterior  part  of  lumbar  region,  behind  peritoneum. 
Placed  on  either  side  of  spinal  column  and  extend  from 
upper  border  of  twelfth  thoracic  to  third  lumbar 
vertebra. 


Q  ^ 


Uriniferous 
tubules 


Capsule  and  j  Covered  by  tough  envelope  of  fibrous  tissue. 

supports    \  Supported  by  quantity  of  fat,  vessels,  and  peritoneum. 

Four  inches  long,  two  inches  broad,  one  inch  thick. 
Weight,  four  and  one  half  ounces  (140  gm.). 
Size  and        J  Bean-shaped,  tubular  glands. 

shape         1  Concave  side  toward  spine,  convex  side  outward. 

Hilum  —  depression  near  centre  of  concave  side  serves 
for  vessels  to  enter  and  leave. 

Pelvis  —  Upper  expanded  end  of  ureter. 

Calyces  —  Cup-like  cavities  of  the  pelvis  that  receive 

papillae  of  pyramids. 
Cortex  — ■  outer,  lighter,  more  solid  portion. 
Medulla  —  inner,  darker,  striated  portion. 

'  Begin  as  hollow  globes  or  capsules  in  the 
cortex  of  kidney,  and  after  a  very  ir- 

{  regular  course  open  into  straight  col- 
lecting tubes  which  pour  their  contents 
into  calyces  of  pelvis. 

Cone-shaped  masses  in  the  medullary 
portion  of  the  kidney.     Vary  in  num- 
ber from  8-12. 
Anatomy  Bases  directed  toward  cortex. 

of  the         i  Pyramids     <  Papillae  —  Apices  of   the   pyramids,  di- 
kidney  rected  toward  pelvis. 

Consist  of  uriniferous  tubules,  blood- 
vessels, and  l}Tnphatics,  held  together 
by  connective  tissue. 

(Minute  tufts  of  capillaries  —  glomeruli 
—  in  the  cortical  portion  of  kidneys 
which  are  surrounded  by  inverted  cap- 
sule of  uriniferous  tubule. 

'  Renal  artery  —  direct  from  aorta. 
Enters  hilus  of  kidney,  divides  into  many 
branches. 

C  Lateral  branches  at  the  level  of 
the  base  of  the  pyramids. 


Blood 
supply 


Arterial 
arches 


1.  Send    branches    to    cortex 
(cortical) . 
.  2.  Send  branches  to  pyramids. 


340 


ANATOMY   FOR   NURSES  [Chap.  XVll 


Anatomy 
of  the 
kidney 


Blood 
supply 


Nerves  and 
lymphat- 
ics 


Function 


Ureters 


Bladder 


Lateral   branches  at   level  of 

Venous  j      base  of  pyramids, 
arches  i  Receive  blood  from  cortex. 

i  Receive  blood  from  pyramids. 

Veins  empty  into  renal  vein,  leave 
kidney  at  hilus,  and  empty  into  in- 
ferior vena  cava. 

Note  —  Blood  from  renal  artery  serves 
for  purposes  of  nourishment  of  kidney 
and  purposes  of  excretion. 

Nerves  from  sjTnpathetic  and  central 
nervous  system. 

Many  are  vasomotor,  and  by  regulating 
size  of  blood-vessels,  influence  blood 
pressure. 

Well  supplied  with  IjTnphatics. 

1.  Process  of  transudation  or  filtration. 
Water  and  saline  elements  are  fil- 
tered from  the  blood  during  the  cir- 
culation through  the  glomeruli. 

2.  Secretory  action  of  the  cells  lining 
the  uriniferous  tubules.  Urea  and 
other  foreign  substances  are  sepn 
arated  from  the  blood  during  the 
circulation  through  the  plexus  of 
capillaries  which  surrounds  the 
tubules. 

Excretory  ducts.     Extend  from  kidney  to  bladder. 
Consist  of  expanded  portion  called  pehas  and  duct. 
Size  of  goose-quill.     12-18  in.  long. 
C  1.  Mucous  —  lining. 

'  2.  Muscular  1 1^""'"'  l«"gitudinal  layer. 
I  Outer,  circular  layer. 
3.  Fibrous  —  carries  blood-vessels  and  nerves. 
r  Connect  kidneys  with  bladder. 
\  Passageway  for  urine. 

Hollow  muscular  organ. 

in  front  of  rectum  in  male, 
in    front    of    anterior    wall    of 


Secretion 
of  urine 


Three 
coats 

Function 


Situated  in  pelvic  cavity 
behind  the  pubes 


vagina  and  neck  of  uterus  in 
female. 


Chap,  XVII] 


SUMMARY 


341 


Four  coats 


Function 


Freely  movable.     Held  in  position  by  ligaments. 

Size,  shape,  and  position  depend  upon  age,  sex,  and  whether 

bladder  is  full  or  empty. 
Fundus  —  widest  part. 

Cervix  —  where  the  bladder  becomes  contmuous  with  the 
urethra. 

1.  Mucous  —  lining. 
Bladder         j  2.  Areolar  —  connects  mucous  and  muscular. 

f  Inner  layer  —  longitudinal. 

3.  Muscular    Middle  layer  —  circular. 
[  Outer  layer  —  longitudinal. 

4.  Serous  —  partial  covermg  derived  from  peri- 
toneum. 

r  Serves  as  a  reservoir  for  the  reception  of  urine. 
j  When  moderately  distended,  holds  about  one 
[      pint. 

'  Membranous  canal,  extends  from  the  bladder  to  the  meatus 

urinarius.     li  in.  long  and  i  in.  in  diameter  in  female. 
Behind  symphysis  pubis,  and  embedded  in  the  anterior 
wall  of  vagina. 
Urethra  I  f  1.  Mucous  —  lining. 

2.  Submucous  —  supports  network  of  veins. 

3.  Muscular  |  ^''''^^  ~  longitudinal. 
I  External  —  circular. 

Meatus  urinarius  —  external  orifice  located  between  cU- 
toris  and  vagina. 

Act  of  expelling  urine  from  bladder. 
Micturition    I  Occurs  as  result  of  irritation  due  to  accumulation  of  urine 
in  bladder. 
Involuntary  act  —  can  be  controlled  by  voluntary  effort. 
Failure  to  void  urine. 

'  1.  DuUing  of  the  senses. 
Due  to       j  2-  Nervous  contraction  of  urethra. 

3.  Some   obstruction   in  urethra  or  neck  of 
bladder. 
May  be  accompanied  by  overflow  or  constant  voiding  of 
small  amounts. 

Suppression  —  Failure  of  the  kidneys  to  secrete  urine. 

Transparency  —  depends  on  absence  or  presence  of  mucus 
and  pus. 

Color  —  depends  on  concentration.  Relative  amoimts  of 
water  and  solids. 

Reaction  —  usually  acid. 

Specific  gravity  —  average  1.020.  Depends  on  concentra- 
tion. 


Three 
coats 


Retention 


Characters 
of  Urine 


342 


ANATOMY   FOR  NURSES         [Chap.  XVII 


Characters 
of  Urine 


Average  40  to  50  ounces. 

Action  of  diuretics. 
Nervousness. 

'  Diabetes     in- 


Quantity    ■ 


Increased 
by 


Decreased 
by 


Urine 


Water, 
95  per  cent 


Solids, 
5  per  cent 


Organic, 
about  3.7 


Inorganic, 
about  1.3 


sipidus. 
Certain  disease  i  Diabetes  mel- 

litus. 
,  Hysteria. 
Ingestion  of  small  amounts  of 

water. 
Vomiting,  diarrhoea. 
High  fever. 
Disease  of  kidneys. 
Increased  action  of  skiu. 


Urea  (2  per  cent  of  total  solids). 

Uric  acid. 

Creatinin. 

Hippuric  acid. 

Other  substances. 

Sodium  chloride. 

Sulphates. 


Salts  of 


Urea 


Phosphates. 

Potassium. 

Ammonium. 

Magnesimn. 

Calcium. 

Other  substances. 

End  product  resulting  from  metabolism  of  proteins. 
Average  excreted  in  twenty-four  hours  —  1  ounce. 

Increased   (  ^'^^  "^^^  ^^  proteins. 

1^  <  Strenuous  exercise. 

I  Fever,  and  some  diseases. 

T^  I  (  Small  amount  of  protein  food. 

Decreased  \  ^         .  -x-       r  •    x- 

<  Excessive  vomitmg,  free  perspiration. 

I  Diseases  that  interfere  with  elimination. 


by 


Uric  acid 

Creatinin 

Hippuric 
Acid 


r  End  product  resulting  from  oxidation  of  tissues. 

<  Combines  with  potassium  and  sodium  to  form  urates. 

I  Failure  to  excrete  results  in  gout. 

f  May  be  taken  into  body  in  food. 

I  Formed  in  body  by  oxidation  of  certain  proteins. 

IMay  be  derived  from  oxidation  of  proteins. 
Maj'  result  from  putrefactive  processes  in  the  intestines. 
Increased  by  a  vegetable  diet. 


Chap.  XVII] 


SUMMARY 


343 


Salts 


Abnormal 
Constitu- 
ents 


r  Derived  from  food  eaten. 

I  Derived  from  neutralization  of  acids. 

I  Sodium  chloride  is  most  abundant. 

Albumin. 
Glucose. 
Indican. 
Acetone. 
Casts. 
Calculi. 
Pus. 
I  Blood. 


CHAPTER   XVIII 

THE  SKIN;  APPENDAGES  OF  THE  SKIN.     PRODUCTION  OF  HEAT; 
REGULATION    OF    HEAT.     VARIATIONS    IN    TEMPERATURE 

THE   SKIN 

Functions.  —  The  skin  is  not,  like  the  kidneys,  set  apart  to  per- 
form one  special  function.  It  serves:  (1)  as  a  protective  cover- 
ing for  the  deeper  tissues  lying  beneath  it,  (2)  as  a  sense  organ, 
(3)  as  an  excretory  organ,  (4)  as  an  absorbing  organ,  (5)  as  an 
important  organ  in  heat  regulation,  and  (6)  as  a  respiratory  organ. 

Structure.  —  It  consists  of  two  distinct  layers :  — 

(1)  Epidermis,  scarf  skin,  or  cuticle. 

(2)  Derma,  cutis  vera,  or  corium. 

Epidermis.  —  The  epidermis  is  a  stratified  epithehum,  com- 
posed of  a  number  of  layers  of  cells.  The  thickness  varies  in 
different  parts  of  the  body,  measuring  in  some  places  not  more 
than  oi^  inch  (0.104  mm.),  and  in  others  as  much  as  o^  inch 
(1.04  mm.).  It  is  thickest  in  the  palms  of  the  hands  and  on  the 
soles  of  the  feet,  where  the  skin  is  most  exposed  to  friction,  and 
thinnest  on  the  ventral  surface  of  the  trunk,  and  the  inner  surfaces 
of  the  limbs.  It  forms  a  protective  covering  over  every  part  of 
the  true  skin,  upon  which  it  is  closely  moulded. 

It  is  roughly  divisible  into  two  layers  :  — 

(1)  Upper,  or  Horny. 

(2)  Germinative,  or  Malpighian. 

(1)  The  horny  layer  consists  of  three  strata  of  cells,  which  are 
practically  dead,  and  are  constantly  being  shed  and  renewed  from 
the  cells  of  the  germinative  layer. 

(2)  The  germinative  layer  consists  of  soft  protoplasmic  cells. 
The  growth  of  the  epidermis  takes  place  by  the  multiplication 

of  these  cells.  As  they  multiply  they  push  upward  toward  the 
surface  those  previously  formed.  In  their  upward  progress 
they  undergo  a  chemical  transformation,  and  the  soft  proto- 
plasmic cells  become  converted  into  the  flat,  horny  scales  which 

344 


Chap.  XVIII] 


THE  SKIN 


345 


are  constantly  being  rubbed  off  the  surface  of  the  skin.  The  pig- 
ment in  the  skin  of  the  negro,  as  well  as  that  of  the  nipple  in  white 
races,  is  found  in  the  deepest  cells  of  the  germinative  layer.' 

No  blood-vessels  pass  into  the  epidermis ;   it,  however,  receives 
fine  nerve-fibrils  between  the  cells  of  the  germinative  layer. 


Horny  < 


corneum 

stratum  lucidum 

stratum 

-ranulos.uin 


O.  or  M/ 


> 


Germinative 

or 
Malpighian 


■m. 


^e 


,4^; 


^X'i 


Fig.  170.  —  Vertical  Section  throttgh  the  Skin  of  the  Palmar  Side  of 
THE  Finger,  showing  Two  Papill.e  (One  of  which  contains  a  Tactile  Cor- 
puscle) AND  the  Deeper  Layer  of  the  Epidermis.     (Schafer.) 

Derma.  —  The  derma  is  a  highly  sensitive  and  vascular  layer 
of  connective  tissue.     It  is  described  as  consisting  of  two  layers  :  — 

(1)  Superficial,  or  papillary  layer. 

(2)  Deeper,  or  reticular  layer. 

(1)  The  surface  of  the  papillary  layer  is  increased  by  protru- 
sions in  the  form  of  small  conical  elevations,  called  papillse,  whence 
this  layer  derives  its  name.  They  project  up  into  the  epidermis, 
which  is  moulded  over  them,  and  contain  for  the  most  part  looped 
blood-vessels,  but  they  also  contain  the  terminations  of  nerve- 
fibres  in  the  shape  of  little  bodies  called  tactile  corpuscles. 


34G  ANATOMY  FOR   NURSES       [Chap.  XVIII 

The  papillae  seem  to  exist  chiefly  for  the  purpose  of  giving  the 
skin  its  sense  of  touch,  being  always  well  developed  where  the 
sense  of  touch  is  exquisite.  They  are  specially  large  and  numerous 
on  the  palm  of  the  hand  and  the  tips  of  the  fingers,  and  on  the  cor- 
responding parts  of  the  foot. 

(2)  The  reticular  layer  of  the  corium  is  a  continuation  of 
the  papillary  layer,  there  being  no  real  division  between  them. 
It  is  made  up  of  bundles  of  white  fibrous  and  elastic  tissue. 

The  derma  is  attached  to  the  parts  beneath  it  by  a  layer 
of  areolar  tissue,  here  named  subcutaneous,  which  layer,  with 
very  few  exceptions,  contains  fat.  The  connection  in  some 
parts  is  loose  and  movable,  as  on  the  front  of  the  neck ;  in  others, 
close  and  firm,  as  on  the  palmar  surface  of  the  hand  and  the  sole 
of  tlic  foot. 

Blood-vessels.  —  The  blood-vessels  of  the  skin  are  found  in  the 
derma  only.  They  form  a  network  of  capillaries  in  which  the  ves- 
sels are  very  close  to  each  other,  and  send  branches  to  the  papilhe 
and  glands  of  the  skin.  The  capillaries  of  the  skin  r.re  capable  of 
holding  from  one-half  to  two-thirds  of  the  blood  contained  in  the 
body.  The  amount  of  blood  they  contain  is  dependent  on  their 
calibre,  and  this  is  regulated  largely  by  the  vasomotor  nerves. 

Nerves.  —  The  skin  is  provided  with  a  great  variety  of  nerves. 
They  are  classified  as  follows  :  — 

(1)  Vasomotor  nerves,  which  are  distributed  in  the  walls  of  the 
blood-vessels. 

(2)  Two  sets  of  nerves  concerned  in  the  temperature  sense, 
which  terminate  in  the  hot  and  cold  spots  of  the  skin. 

(3)  The  nerves  concerned  in  the  sense  of  touch  or  pressure. 

(4)  Nerves  which  are  stimulated  by  pain. 

(5)  Motor  nerves,  which  are  derived  from  the  sympathetic  sys- 
tem and  distributed  to  the  glands  and  the  arrector  muscles. 

Nearly  every  nerve  centre  in  the  body  may  be  affected  by  sensa- 
tions arising  in  the  skin,  because  of  the  number  of  afferent  nerves 
which  lead  from  the  skin  to  centres  in  the  brain  and  spinal  cord. 
It  is  for  this  reason  that  hydrotherapeutic  applications,  heat,  cold, 
and  counter  irritants  excite  so  many  and  such  varied  reflexes. 


Chap.  XVIII] 


THE   SKIN 


347 


LUNULA..  ^ 


Fig.  171.  —  Thumb-nail. 
(Geirish.) 


THE    APPENDAGES  OF  THE  SKIN 

The  appendages  of  the  skin  are  the  nails,  the  hair,  the  sebaceous 

glands,  the  ceruminous  glands,  and  the  sudoriferous  or  sweat-glands. 
The  nails.  —  The  nails  are  composed  of  clear,  horny  cells  of 

the  epidermis,  joined  together  so  as  to  form  a  solid,  continuous 

plate.     Each  nail  is  convex  on  its  outer 

surface,  concave  on  its  inner  side,  and 

closely  adherent  to  the  underlying  derma, 

which  is  modified  to  form  what  is  called 

the  bed,  or  matrix,  of  the  nail.     At  the 

hinder  part  of  the  bed  of  the  nail  the  skin 

forms  a  deep  fold,  in  which  is  lodged  the 

root  of  the  nail. 

The  growth  of  the  nail  is  accomplished 

by  constant  multiplication  of  the  soft  cells 

in   the    germinative    layer    at   the    root. 

These  cells  are  transformed  into  dry,  hard 

scales,  which  unite  into  a  solid  plate,  and 

the  nail,  constantly  receiving  additions  from  below,  slides  forward 
over  its  bed  and  projects  beyond  the  end  of 
the  finger.  When  a  nail  is  thrown  off  by 
suppuration  or  torn  oft'  by  violence,  a  new 
one  will  grow  in  its  place  provided  any  of 
the  cells  of  the  germinative  layer  are  left. 

The  hair.  —  The  hair  is  a  growth  of  the 
epidermis,  developed  in  little  pits,  the  hair- 
follicles,  which  extend  downward  into  the 
deeper  part  of  the  true  skin,  or  even  into 
the  subcutaneous  tissue.  The  hair  grows 
from  the  bottom  of  the  little  pit  or  follicle. 
The  part  which  lies  within  the  follicle  is 
known  as  the  root,  and  that  portion  which 
projects  beyond  the  surface  of  the  skin  is 
called  the  shaft  or  stem.  The  substance  of 
the  hair  is  composed  of  coalesced,  horny 
cells,  arranged  in  different  layers,  and  we 

usually  distinguish  three  parts  in  the  stem  or  shaft  of  a  hair :  — 

(1)  Cuticle  —  an  outer  layer  of  delicate,  scale-like  cells. 

(2)  Fibrous  substance  —  a  middle,  horny,  thick  portion,  formed 


Fig.  172.  —  Piece  of 
Human  Hair.  (Highly 
magnified.)  a,  cuticle ; 
b,  fibrous  substance ;  c, 
medulla. 


348  ANATOMY   FOR   NURSES        [Chap.  XVIII 

of  elongated  cells.  These  cells  and  the  intercellular  spaces  contain 
a  varying  amount  of  pigment,  and  the  color  of  the  hair  depends 
upon  the  quantity.  The  gray  hair  of  old  age  is  produced  by  loss 
of  pigment. 

(3)  Medulla  —  a  central  pith  formed  of  round  cells.  Minute  air 
bubbles  may  be  present  in  both  the  medulla  and  fibrous  layer, 
and  cause  the  hair  to  look  white  by  reflected  light. 

The  root  of  the  hair  is  enlarged  at  the  bottom  of  the  follicle 
into  a  bulb  or  knob.  This  bulb  is  composed  of  soft-growing 
cells,  and  fits  over  a  vascular  papilla  which  projects  into  the 
bottom  of  the  follicle.  Hair  has  no  blood-vessels  but  receives 
nourishment  from  the  blood  vessels  of  the  papilla. 

Growth  of  hair.  —  Hair  grows  from  the  bottom  of  the  follicle 
by  multiplication  of  the  soft  cells  which  cover  the  papilla.  These 
cells  become  elongated  to  form  the  fibres  of  the  fibrous  portion, 
and  as  they  are  pushed  to  the  surface,  they  become  flattened  and 
form  the  cuticle.  If  the  scalp  is  thick,  pliable,  and  moves  freely 
over  the  skull  it  is  favorable  to  the  growth  of  hair.  A  thin  scalp 
that  is  drawn  tightly  over  the  skull  tends  to  constrict  the  blood- 
vessels, lessen  the  supply  of  blood,  and  cause  atrophy  of  the  roots 
of  the  hair  by  pressure.  In  such  cases  massage  of  the  head  loosens 
the  scalp,  improves  the  circulation  of  the  blood,  and  usually  stimu- 
lates the  growth  of  hair. 

With  the  exceptions  of  the  palms  of  the  hands,  the  soles  of  the 
feet,  and  the  last  phalanges  of  the  fingers  and  toes,  the  whole 
skin  is  studded  with  hair.  The  hair  of  the  scalp  is  long  and  coarse, 
but  most  of  the  hair  is  very  fine  and  extends  only  a  little  beyond  the 
hair  follicle. 

Arrector  muscles.  —  The  follicles  containing  the  hairs  are  narrow 
pits  which  slant  obliquely  upward,  so  that  the  hairs  they  contain 
lie  down  on  the  surface  of  the  body.  Connected  with  each  follicle 
is  a  small  muscle  called  the  arrector  muscle.  It  is  composed  of 
bundles  of  plain  muscular  tissue  which  pass  from  the  surface 
of  the  true  skin,  on  the  side  to  which  the  hair  slopes,  obliquely 
downward,  to  be  attached  to  the  bottom  of  the  follicle.  When 
these  muscles  contract,  as  they  will  under  the  influence  of  cold  or 
terror,  the  little  hairs  are  pulled  up  straight,  and  stand  "  on  end  "  ; 
the  follicle  also  is  dragged  upward,  and  in  this  way  the  roughened 
condition  of  the  skin  known  as  "  gooseflesh,"  is  produced. 


Chap.  XVIII] 


THE  SKIN 


349 


Sebaceous  glands.  —  The  sebaceous  glands  are  small,  saccular 
glands,  which  lie  between  the  hairs  and  their  arrector  muscles. 
They  occur  everywhere  over  the  skin  surface,  with  the  exception 
of  the  palms  of  the  hands  and  the  soles  of  the  feet. 

Each  gland  consists  of  a  collection  of  small  tubes  overspread 
with  a  network  of  capillaries.  From  the  gland  a  small  duct  as- 
cends, and  opens  either  upon  the  surface  of  the  skin  or,  as  is  more 


SUBCUTANEOUS 
AREOLAR  TISSUE 


DUCT  OF 

SEBACEOUS 

GUND 


T— ROOT  OF  HAIR 

HAIR  FOLLICLE 

— -ADIPOSE  TISSUE 


BULB  OF  HAIR 
PAPILLA  OFHAIB 


ARRECTOR  MUSCLE 


Fig.  173.  —  Vertical  Section  of  the  Skin,   showing  Sebaceous  Glands, 
Sweat-glands,  Hair,  and  Follicle,  also  Arrector  Muscle.     (Gerrish.) 


common,  into  a  hair  follicle.  Their  size  is  not  regulated  by  the 
length  of  the  hair.  Thus,  some  of  the  largest  are  found  on  the 
nostrils  and  other  parts  of  the  face,  where  they  often  become  en- 
larged with  pent-up  secretion. 

Sebum.  —  The  secretion  of  the  sebaceous  glands  is  called  sebum. 
It  contains  fats,  soaps,  epithelial  cells,  albuminous  matter  and 
inorganic  salts.  It  serves  to  remove  waste  matters  and  is  classed 
as  an  excretion,  but  its  more  important  purposes  are  to  keep  the 
skin  and  hair  soft  and  pliable,  and  to  form  a  protective  layer  on 


350 


ANATOMY  FOR   NURSES        [Chap.  XVIII 


the  surface  of  the  skin.  An  accumulation  of  this  sebaceous  matter 
upon  the  skin  of  the  foetus  furnishes  the  thick,  cheesy,  oily  sub- 
stance called  the  vemix  caseosa. 

Ceruminous  glands.  —  The  skin  lining  the  external  auditory 
canal  contains  modified  sweat  glands  called  ceruminous  glands. 
They  secrete  a  yellow,  pasty  substance  resembling  wax  which  is 
called  cerumen. 

Sweat-glands. — The  sweat-glands  are  simple,  convoluted,  tubu- 
lar glands  with  the  blind  ends  coiled  into  little  balls  which  are 

lodgetl  in  the  true  skin  or 
subcutaneous  tissue ;  from 
the  ball  the  tube  is  con- 
tinued as  the  excretory 
duct  of  the  gland  up 
through  the  true  skin  and 
epidermis,  and  finally 
opens  on  the  surface  by 
a  slightly  widened  orifice 
called  a  pore.  Each  tube 
is  lined  by  a  secreting  epi- 
thelium continuous  with 
the  epidermis.  The  coiled 
end  is  closely  invested  by 
a  meshwork  of  capillaries, 
and  the  blood  in  the  cap- 
illaries is  only  separated  from  the  cavity  of  the  glandular  tube  by 
the  thin  membranes  which  form  their  respective  walls.  The  secre- 
tory apparatus  in  the  skin  is  somewhat  similar  to  that  which 
obtains  in  the  kidneys;  in  the  one  case  the  blood-vessels  are 
coiled  up  within  the  tube,  while  in  the  other  the  tube  is  coiled  up 
within  the  meshwork  of  blood-vessels. 

The  sweat-glands  are  abundant  over  the  whole  skin,  but  they 
are  largest  and  most  numerous  in  the  axillae,  the  palms  of  the 
hands,  soles  of  the  feet,  and  the  forehead. 

Perspiration,  or  sweat.  —  The  sweat  is  a  watery,  colorless 
liquid,  slightly  turbid,  of  a  salty  taste,  with  a  strong,  distinctive 
odor  and  an  acid  reaction.  It  is  an  excrement,  the  chief  normal 
constituents  of  which  are  water,  salts,  fatty  acids,  a  small 
quantity  of  carbon  dioxide,  and  a  slight  amount  of  urea.     In  vari- 


FiG.  174.  —  Coiled  End  of  a  Sweat-gland. 
a,  the  coiled  end ;  b,  the  duct ;  c,  network  of 
capillaries,  inside  which  the  sweat-gland  lies. 


Chap.  XVIII]  THE  SKIN  351 

ous  forms  of  kidney  disease  urea  may  be  present  in  considerable 
quantity,  the  skin  supplementing  to  a  certain  extent  the  deficient 
work  of  the  kidneys. 

Quantity  of  perspiration.  —  Under  ordinary  circumstances,  the 
perspiration  that  we  are  continually  throwing  off  evaporates 
from  the  surface  of  the  body  without  our  becoming  sensible  of  it, 
and  is  called  insensible  perspiration.  When  more  sweat  is  poured 
upon  the  surface  of  the  body  than  can  be  removed  at  once  by 
evaporation,  it  appears  on  the  skin  in  the  form  of  drops,  and  we 
then  speak  of  it  as  sensible  perspiration. 

The  average  amount  discharged  during  twenty-four  hours  is 
about  one  quart  (0.946  litre),  but  it  may  be  increased  to  such  an 
extent  that  even  more  may  be  discharged  in  an  hour.  The  secre- 
tion of  sweat  is  increased  by:  (1)  a  dilute  condition  of  the  blood, 
such  as  results  from  drinking  large  quantities  of  liquids,  (2)  in- 
creased temperature  or  humidity  of  the  atmosphere,  (3)  exercise, 
(4)  pain,  (5)  mental  excitement  or  nervousness,  (6)  dyspnoea, 
(7)  use  of  diaphoretics,  (8)  certain  diseases  such  as  tuberculosis, 
acute  rheumatism,  and  malaria,  (9)  use  of  electricity  to  stimulate 
the  secretory  nerves. 

The  secretion  of  sweat  is  decreased  by:  (1)  voiding  of  a  large 
quantity  of  urine,  (2)  cold,  (3)  diarrhoea,  (4)  certain  drugs,  and 
•  (5)  certain  diseases,  such  as  fevers,  diabetes,  and  some  cases  of 
paralysis. 

Activity  of  the  sweat-glands.  —  The  activity  of  the  sweat-glands 
is  supposed  to  be  due  to  direct  stimulation  of  the  nerve  endings  in 
the  glands,  or  indirect  stimulation  of  the  nerve  centres  controlling 
perspiration.  An  increase  in  perspiration  following  an  increase  in 
the  temperature  or  humidity  of  the  atmosphere  is  partly  due  to 
stimulation  of  the  nerve  endings  in  the  sweat-glands,  and  partly 
due  to  the  stimulation  from  the  sensory  nerves  being  carried  to 
the  nerve  centres,  and  transmitted  along  motor  nerves  to  the 
gland.  The  activity  is  also  influenced  by  the  vasomotor  nerves, 
which  control  the  size  of  the  blood-vessels  in  the  skin  ;  an  increase 
in  the  size  of  the  vessels  leads  to  increased,  a  constriction  of  the 
vessels  to  diminished,  perspiration.  That  this  is  not  the  only 
factor  is  proven  by  the  profuse  perspiration  that  often  accompanies 
a  pallid  skin,  or  the  absence  of  perspiration  that  is  characteristic 
of  fever. 


352  ANATOMY   FOR  NURSES        [Chap.  XVIII 

Excretory  function  of  the  skin.  —  While  sweat  is  an  excretion, 
its  value  lies  not  so  much  in  the  elimination  of  waste  matter  as  in 
the  loss  of  body  heat  by  the  evaporation  of  water.  This  loss  of 
heat  is  necessary  to  balance  the  production  of  heat  that  is  con- 
stantly taking  place. 

Less  important  functions  of  the  skin.  —  The  skin  is  to  a  slight 
extent  an  absorbing  organ.  Soluble  substances  are  very  readily 
absorbed  if  the  epidermis  is  removed,  but  even  when  in  solution 
they  are  sparingly  absorbed  by  the  unbroken  skin.  Oily  sub- 
stances, if  well  rubbed  in,  are  readily  absorbed,  especially  in  those 
parts  of  the  body  where  the  epidermis  is  thinnest. 

Oxj'gen  in  small  amount  is  also  taken  in  through  the  skin,  but 
this  gain  to  the  body  is  counterbalanced  by  the  carbon  dioxide 
which  is  thrown  off. 

BODY  HEAT 

From  the  standpoint  of  heat,  production  animals  may  be  divided 
into  two  great  classes  :  — 

(1)  Constant  temperature  animals,  or  those  whose  temperature 
remains  practically  constant  whether  the  surrounding  air  is  hotter 
or  cooler  than  the  body.  The  term  warm-blooded  is  also  applied 
to  this  class.     It  includes  human  beings. 

(2)  Changeable  temperature  animals,  or  those  whose  tempera- 
ture varies  with  that  of  the  surrounding  medium.  This  class  is 
also  described  as  cold-blooded.     The  human  foetus  is  cold-blooded. 

The  great  difference  between  these  two  classes  is  in  their  reac- 
tions to  external  temperature.  A  cold  environment  reduces  the 
temperature  of  the  cold-blooded  creature,  reduces  the  metabolism 
of  all  its  tissues,  and  thus  reduces  its  heat  production.  The 
warm-blooded  animal  reacts  in  precisely  the  opposite  way.  Since 
his  temperature  remains  constant,  his  heat  production  must  in- 
crease in  order  to  neutralize  the  effect  of  cold  surroundings. 

Production  of  heat.  —  Heat  in  the  body  is  produced  by  such 
chemical  changes  going  on  in  the  tissues  as  are  associated  with 
oxidation.  Friction  is  a  minor  source  of  heat,  i.e.  that  caused  by 
the  movements  of  the  muscles,  the  circulation  of  the  blood,  and 
the  ingestion  of  warm  food. 

Where  heat  is  produced.  —  Wherever  metabolic  changes  are 
taking  place,  there  heat  is  set  free.     These  changes  take  place 


Chap.  XVIII]  BODY   HEAT  353 

more  rapidly  in  some  tissues  than  in  others,  and  in  the  same  tissues 
at  different  times.  The  muscles  always  manifest  a  far  higher  rate 
of  activity  than  the  connective  tissues,  and  consequently  the 
former  evolve  a  larger  proportion  of  the  bodily  heat  than  the  latter. 
We  might  liken  the  different  tissues  of  the  body  to  so  many  fire- 
places stored  with  fuel,  the  fuel  in  some  of  the  fireplaces  being  more 
easily  ignited  and  burning  more  rapidly  than  in  others.  The 
muscles  and  the  secreting  glands,  especially  the  liver,  are  sup- 
posed to  be  the  main  sources  of  heat,  as  they  are  the  seats  of  a  very 
active  metabolism. 

Loss  of  heat.  —  The  heat  thus  continually  produced  is  as  con- 
tinually leaving  the  body  by  the  skin  and  the  lungs,  and  by  the 
urine  and  feces.  It  has  been  calculated  that  in  every  100  parts 
about : — 

88  per  cent  is  lost  by  conduction  and  radiation  from  the  sur- 
face of  the  skin  and  the  evaporation  of  the  perspiration. 

9  per  cent  is  lost  by  warming  the  expired  air  and  the  evapora- 
tion of  the  water  of  respiration. 

3  per  cent  is  lost  by  warming  the  urine  and  feces. 

The  temperature  and  humidity  of  the  atmosphere  may  cause 
considerable  difference  in  the  per  cents  given  above.  A  low  tem- 
perature will  increase  the  loss  of  heat  by  radiation  and  decrease 
that  by  evaporation.  A  high  temperature  will  decrease  the  loss 
of  heat  by  radiation  and  increase  that  by  evaporation  owing  to 
the  greater  production  of  sweat.  From  the  above  figures  it  is 
evident  that  the  skin  is  the  important  factor  in  getting  rid  of  body 
heat.  This  is  due:  (1)  to  the  large  surface  offered  for  radiation, 
conduction,  and  evaporation ;  and  (2)  to  the  large  amount  of  blood 
which  it  contains. 

Distribution  of  heat.  —  The  blood,  as  we  know,  permeates  all 
the  tissues  in  a  system  of  tubes  or  blood-vessels.  Wherever 
oxidation  takes  place  and  heat  is  generated,  the  temperature  of 
the  blood  circulating  in  these  tissues  is  raised.  Wherever,  on 
the  other  hand,  the  blood-vessels  are  exposed  to  evaporation,  as 
in  the  moist  membranes  in  the  lungs,  or  the  more  or  less  moist 
skin,  the  temperature  of  the  blood  is  lowered.  The  gain  and 
loss  of  heat  balance  one  another  with  great  nicety,  and  the  blood, 
circulating  rapidly,  now  through  warmer,  and  again  through  cooler, 
tubes,  is  kept  at  a  uniform  temperature  of  about  100°  F.  (37.8  C). 
2a 


354  ANATOMY  FOR  NURSES        [Chap.  XVIII 

In  this  way  the  whole  body  is  warmed  in  somewhat  the  same 
way  as  we  warm  a  house,  the  warm  blood  in  the  blood-vessels 
heating  the  tissues,  as  the  hot  water  in  the  hot-water  pipes  heats 
the  rooms  in  water-heated  dwellings. 

THE  REGULATION  OF  HEAT 

The  maintenance  of  the  normal  temperature  of  the  body  is  due : 
(1)  to  the  control  exerted  by  the  nervous  system,  (2)  to  the  regu- 
lation of  muscular  exercise  and  diet,  (3)  to  the  use  of  clothing,  and 
(4)  the  use  of  hot  and  cold  baths. 

Control  of  nervous  system.  —  As  the  amount  of  heat  lost  through 
the  skin  and  lungs  as  well  as  the  metabolism  taking  place  in  the 
body  is  under  the  control  of  the  nervous  system,  it  follows  that  this 
control  is  preeminently  important.  It  is  effected  by  means  of  the 
heat  centres,  the  sensory  nerves,  the  sweat  nerves,  and  the  vaso- 
motor nerves  of  the  skin. 

Heat  regulation  by  the  skin.  —  When  the  external  temperature 
is  high,  tlie  nerve-endings  which  respond  to  heat  are  stimulated, 
and  these  impulses  are  transmitted  over  sensory  nerves  to  the 
nerve  centres  controlling  the  motor  nerves  of  the  sweat-glands. 
The  motor  nerves  stimulate  the  activity  of  the  sweat-glands,  and 
an  increased  amount  of  sweat  is  poured  out  upon  the  surface  of 
the  body.  An  increased  amount  of  heat  is  required  to  vaporize 
this  sweat,  and  thus  heat  is  lost.  Excessive  humidity  interferes 
with  the  evaporation  of  water,  and  thus  interferes  with  the  loss 
of  heat ;  hence  the  discomfort  experienced  on  hot,  humid  days. 

The  sensory  nerves  which  are  stimulated  by  heat  not  only  trans- 
mit impulses  that  stimulate  the  sweat-glands  to  activity,  but  at 
the  same  time  transmit  impulses  that  result  in  the  depression  of 
the  vaso-constrictor  nerves  of  the  arterioles  of  the  skin.  In  con- 
sequence the  arterioles  dilate  and  more  blood  is  sent  to  the  surface 
to  be  cooled.  When  the  external  temperature  is  low,  the  sensory 
nerve  endings  which  are  stimulated  by  cold  transmit  impulses 
which  result  in  stimulation  of  the  vaso-constrictors,  and  conse- 
quent contraction  of  the  arterioles  of  the  skin.  This  lessens  the 
amount  of  blood  in  the  skin  arterioles,  and  lessens  the  amount 
of  heat  lost. 

Heat  regulation  by  respiration.  —  The  stimulation  of  the  sen- 
sory nerves  of  the  skin  that  are  affected  by  cold  influences  the 


Chap.  XVIII]  BODY  HEAT  355 

respiratory  centres,  increases  the  rate  of  the  respirations,  and  con- 
sequently increases  the  loss  of  heat.  In  man  respiration  plays 
only  a  small  part  in  heat  regulation,  but  in  animals  that  do  not 
perspire,  respiration  is  an  important  means  of  regulating  the 
temperature. 

Mechanism  of  heat  regulation.  —  Just  how  the  nervous  system 
controls  the  amount  of  heat  produced  by  metabolism  is  not  known. 
Various  theories  are  advanced,  one  being  that  there  are  special 
nerves  and  special  heat  centres :  (1)  thermogenetic,  which  is 
concerned  in  the  production  of  heat,  (2)  thermolytic,  which  is  con- 
cerned in  the  dissipation  of  heat,  and  (3)  thermotactic,  which  is 
concerned  in  regulating  the  former  two.  Another  theory  is  that 
the  temperature  of  the  blood  influences  the  motor  nerves  of  the 
muscles.  Stimulation  by  cold  causes  increased  contraction  and 
increased  oxidation.  Heat  causes  relaxation  and  a  decrease  in 
oxidation.  Metabolism  is  also  influenced  by  the  action  of  the 
vasomotor  system,  for  under  the  influence  of  cold,  the  blood  is 
driven  to  the  interior  of  the  body  and  metabolism  is  increased; 
under  the  influence  of  heat,  the  blood  is  driven  to  the  surface  of 
the  body  and  metabolism  is  decreased. 

Heat  regulation  by  muscular  exercise  and  diet.  —  Muscular 
contractions  give  rise  to  heat,  therefore  muscular  activity  is  used 
as  a  means  to  counteract  the  effects  of  external  cold.  On  the  other 
hand,  muscular  activity  does  not  increase  the  temperature  in  hot 
weather  to  any  marked  extent.  This  is  accounted  for  by  the 
fact  that  when  muscular  exertion  causes  the  blood  to  circulate 
more  quickly  than  usual,  the  blood-vessels  in  the  skin  dilate,  the 
sweat-glands  at  the  same  time  are  excited  to  pour  out  a  more  abun- 
dant secretion,  and  the  heated  blood  passing  in  larger  quantities 
through  the  cutaneous  vessels  (which  are  kept  well  cooled  by  the 
evaporation  of  the  perspiration),  the  general  average  temperature 
of  the  body  is  maintained. 

During  digestion  heat  is  produced  partly  by  the  peristaltic  ac- 
tion of  the  intestines,  and  partly  by  the  activity  of  the  various 
digestive  glands  (particularly  the  liver).  The  quantity  of  food 
eaten,  and  the  relative  amount  of  heat-producing  food,  influences 
the  temperature  of  the  body.  In  cold  weather  an  increase  in  food 
(usually  accompanied  by  an  increase  of  fats)  serves  to  replace  the 
greater  amount  of  heat  lost.     When  muscular  exercise  is  impos- 


356  ANATOMY   FOR   NURSES        [Chap.  XVIIl 

sibie,  as  in  infants,  an  increase  in  fats  serves  the  same  purpose  as 
exercise  in  a  healthy  aihilt. 

Heat  regulation  by  clothing.  —  By  clothing  we  can  aid  the  func- 
tions of  the  skin  and  the  maintenance  of  heat ;  though,  of  course, 
clothes  are  not  in  themselves  sources  of  heat.  The  object  of 
clothing  is,  in  winter,  to  prevent  conduction,  radiation,  and  evapo- 
ration of  heat  from  the  skin,  and  in  summer  to  promote  it.  In 
considering  the  heat  value  of  clothing  the  important  properties  are : 
(1)  whether  it  is  loosely  or  tightly  woven,  (2)  its  thickness,  and 
(3)  its  color. 

(1)  Materials  that  are  loosely  woven  will  be  warmer  than  those 
that  are  tightly  woven,  because  the  meshes  in  a  loosely  woven 
material  are  capable  of  holding  air,  which  is  a  poor  conductor 
of  heat,  and  thus  prevents  radiation. 

(2)  Thick  material  does  not  allow  cold  air  to  penetrate  to  the 
skin. 

(3)  Dark  colored  materials  absorb  heat  to  some  extent,  hence 
they  are  warmer  than  light  colored  textiles.  Thick,  porous  ma- 
terials are  used  to  keep  the  body  warm.  Wool  has  an  additional 
advantage,  as  evaporation  takes  place  more  slowly  from  it  than 
from  linen,  cotton,  or  silk.  Thin  and  very  porous  materials  help 
to  keep  the  body  cool,  because  they  allow  the  air  to  penetrate  to 
the  skin,  and  thus  assist  the  evaporation  of  sweat. 

Heat  regulation  by  baths.  Hot  baths.  —  The  primary  effect 
of  a  hot  bath  is  to  prevent  radiation  of  heat  from  the  surface  of 
the  body,  and  some  increase  in  temperature  may  result.  If  the 
bath  is  not  continued  for  too  long  a  time,  this  effect  is  counteracted 
by  the  increased  perspiration  that  follows. 

Cold  baths.  —  The  primary  effect  of  a  cold  bath  is  similar  to  the 
effect  of  cold  air.  The  cold  contracts  the  arterioles  of  the  skin, 
drives  the  blood  to  the  interior,  and  increases  oxidation.  If  the 
bath  is  a  short  one  and  is  followed  by  friction,  the  reaction  is  for 
the  arterioles  to  dilate,  the  heated  blood  is  sent  to  the  surface,  the 
circulation  is  quickened,  and  there  is  a  consequent  loss  of  heat. 
In  health  the  gain  in  heat  is  usually  balanced  by  the  loss  of  heat, 
and  the  purpose  of  a  cold  bath  is  to  exercise  the  arterioles  and 
stimulate  the  circulation.  If  the  bath  is  continued  for  some  time, 
the  temperature  of  the  skin,  and  of  the  muscles  lying  beneath,  is 
reduced,  and  either  the  heat-producing  processes  may  be  checked 


Chap.  XVIII]  BODY  HEAT  357 

and  a  loss  of  temperature  result ;  or  shivering  may  intervene.  In 
this  case  the  muscular  contractions  and  constriction  of  the  blood- 
vessels stimulates  metabolism  and  heat  production.  Wnen  cold 
baths  are  given  for  the  purpose  of  increasing  heat  elimination, 
friction  is  used  during  the  bath  to  prevent  shivering.  Friction 
stimulates  the  sensory  nerves  of  the  skin,  causes  dilatation  of  the 
arterioles,  and  favors  the  flow  of  hot  blood  to  the  surface,  thus 
decreasing  the  sensation  of  cold  and  increasing  heat  elimination. 
If  properly  given,  cold  baths  stimulate  the  nervous  system,  improve 
the  tone  of  the  muscles,  including  the  muscles  of  the  heart  and 
blood-vessels,  stimulate  the  circulation,  and  favor  the  elimination 
of  heat. 

VARIATIONS  IN  TEMPERATURE 

Normal  variations.  —  The  temperature  of  the  human  body  is 
usually  measured  by  a  thermometer  placed  in  the  mouth,  axilla, 
or  rectum.  Such  measurements  show  slight  variations,  as  the 
temperature  in  the  interior  of  the  body  is  slightly  higher  than  on 
the  surface  of  the  skin.  The  average  temperature  in  the  rectum  ^ 
is  98.9°  F.,  in  the  axilla  is  98.4°  F.,  in  the  mouth  is  98.3°  F. 

Other  normal  variations  depend  upon  the  manner  of  living, 
time  of  eating,  age,  etc.  The  lowest  temperature  is  usually  in  the 
early  morning,  it  rises  slowly  during  the  day,  reaches  its  maximum 
in  the  evening,  and  falls  again  during  the  night.  This  corresponds 
to  the  usual  temperature  ranges  in  fever,  when  the  maximum  is  in 
the  evening  and  the  minimum  in  the  early  morning.  Muscular 
activity  and  food  may  also  cause  slight  increase  in  temperature 
during  the  day.  Age  has  some  influence.  Infants  and  young 
children  have  a  slightly  higher  temperature  than  adults.  It  is 
also  true  that  the  heat-regulating  mechanism  in  infants^  and  young 
children  is  not  so  efficient  as  in  adults,  consequently  they  are  more 
subject  to  changes  of  body  temperature,  and  these  changes  are  not 
as  significant  as  they  would  be  with  adults.  Aged  people  show  a 
tendency  to  revert  to  infantile  conditions,  and  their  temperature 
is  usually  slightly  higher  than  in  middle  life. 

1  Rectal  temperature  is  the  most  reliable,  and  that  by  mouth  (if  properly  taken) 
is  almost  equally  reliable.     Axillary  temperature  has  little  value. 

*  At  birth  the  heat-regulating  mechanism  is  not  "in  working  order,"  and  during 
the  first  few  weeks  of  life  infants  are  not  able  to  regulate  their  body  temperature, 
hence  the  importance  of  keeping  them  warm.  Premature  infants  are  even  less  able 
to  regulate  their  body  temperature,  hence  need  of  special  means  to  keep  them 
warm. 


358  ANATOMY   FOR  NURSES       [Chap.  XVIII 

Abnormal  variations.  Fever.  —  The  term  fever  is  applied  to 
an  abnormal  condition,  characterized  by  increased  temperature, 
increased  heart-beat,  increased  respiration,  increased  tissue  waste, 
and  faulty  secretion. 

Cause. — The  exact  cause  of  fever  is  unknown.  It  is  the  result 
of  causes  which  disturb  the  balance  between  heat  production  and 
heat  elimination.  One  theory  is  that  there  is  a  heat  centre  in  the 
brain  which  controls  the  production  and  elimination  of  heat,  and 
toxic  substances  circulating  in  the  blood  or  abnormal  conditions 
of  the  various  organs  of  the  body  may  interfere  with  the  proper 
functioning  of  this  centre.  The  toxic  substances  circulating  in 
the  blood  may  result  from  faulty  metabolism,  as  in  diabetes, 
gout,  etc. ;  or  from  the  action  of  bacteria,  as  in  infectious  dis- 
eases ;  or  from  injury  to  the  tissues  of  a  mechanical,  thermal,  or 
chemical  nature. 

Value  of  fever.  —  When  fever  is  due  to  infection  by  bacteria, 
the  body  seems  better  able  to  fight  the  infection  if  the  tempera- 
ture is  elevated.  For  this  reason  fever  is  thought  to  be  a  protective 
measure  and  antipyretics  are  not  used  unless  the  elevation  is  ex- 
treme, or  long  continued.  In  this  case  measures  must  be  taken 
to  reduce  the  temperature,  or  death  may  ensue  from  coagulation 
of  the  proteins  present  in  the  nerve-cells  of  the  brain  and  spinal 
cord. 

Subnormal  temperature.  —  In  some  maladies  the  temperature 
falls  distinctly  below  normal.  This  is  no  doubt  chiefly  due  to 
diminished  metabolism.  In  cases  of  starvation  the  fall  of  tem- 
perature is  very  marked,  especially  during  the  last  days  of  life. 
The  diminished  activity  of  the  tissues  first  affects  the  central 
nervous  system ;  the  patient  becomes  languid  and  drowsy,  and 
finally  unconscious ;  the  heart  beats  more  and  more  feebly,  the 
breath  comes  more  and  more  slowly,  and  the  sleep  of  unconscious- 
ness passes  insensibly  into  the  sleep  of  death. 


Chap.  XVIII] 


SUMMARY 


359 


Func- 
tions 


Skin<^ 


SUMMARY 

1.  Protective  covering  for  deeper  tissues. 

2.  As  a  sense  organ. 

3.  As  an  excretory  organ  —  Elimination  of  waste  matter 

in  sweat. 

'  Absorption  through  unbroken 

A     A„„«    u      u-  skin  is  limited. 

4.  As  an  absorbmg  organ  <   . , 

I  Absorption  rapid  if  epidermis 
[      is  removed. 

5.  Most  important  as  organ  in  heat  regulation. 
Small  amount  oxj'gen  taken  in. 
Small  amount  carbon  dioxide 

is  thrown  off. 

'  Practically 
dead  cells 
being  con- 
stantlj^  shed 
and  renewed 
from  germi- 
native  layer. 


6.  As  a  respiratory  organ 


Epidermis 
is  a  strati- 
fied epi- 
theUum 


1.  Superfi- 
cial   or 
horny 


b. 


Soft  protoplasmic  cells  that 
are  constantly  multiplying 
by  cell  division. 


Stratum 

corneum 
Stratum 
lucidum 
Stratum 
granulo- 
sum 
Germina- 
tive  or 
Con-       I  Mal- 

sists  of  1  I  pighian 

Papillary  layer  —  papillae  are  minute  coni- 
cal elevations  of  the  cutis  vera.     They 
Derma    is  contain  looped  blood-vessels  and  ter- 

a   layer  minations  of  nerve-fibres  called  tactile 

of    con-  {  corpuscles. 

nective  f  Bundles  of  fibrous  and  elastic 

tissue        2.  Reticular  I      tissue,     with    network    of 
layer  blood-vessels,     lymphatics, 

and  nerves. 

Blood-vessels  —  They  are  found  in  derma  only.     Send  branches 
to  papillae  and  glands  of  skin.     Capable  of  holding  one-half  to 
two-thirds  total  amount  of  blood  in  body. 
f  1.  Vasomotor. 
2.  Two  sets  concerned  in  temperature  sense. 
Nerves  {  3.  Nerves  concerned  in  sense  of  touch  or  pressure. 

4.  Nerves  stimulated  by  pain. 

5.  ]\[otor  nerves  from  sympathetic  system. 
r  Nails. 


Appendages 


Hair. 

Sebaceous  glands. 

Ceruminous  glands. 

Sweat-glands. 


360 


ANATOMY  FOR  NURSES       [Chap.  XVIIJ 


Nails 


Hair 


Sebaceous 
Glands 


Ceruminous 
Glands 


Sweat- 
glands 


Sweat 


Found     all     over 
body,  except 


[  Consist  of  clear,  horny  cells  of  epidermis. 
j  True  skin  forms  a  bed  or  matrix  for  nail. 

Root  of  nail  is  lodged  in  a  deep  fold  of  the  skin. 

Nails  grow  from  soft  cells  in  gerrainative  layer  at  root. 

The  hair  grows  from  the  roots. 

The  roots  are  bulbs  of  soft-growing  cells  contained  in  the 
hair  follicles. 

Hair  follicles  are  little  pits  developed  in  the  derma. 

Stems  of  hair  extend  beyond  the  surface  of  the  skin,  con- 
sist of  three  layers  of  cells:  (1)  cuticle.  (2)  fibrous 
substance.     (3)  medulla. 

(Palms  of  the  hands. 
Soles  of  the  feet. 
Last  phalanges  of  the  fingers  and  toes. 
Arrector  muscles  are  attached  to  true  skin  and  to  each  hair 
follicle. 

Saccular  glands  the  ducts  of  which  usually  open  into  a 
hair  follicle,  but  may  discharge  separately  on  the  sm- 
face  of  the  skin. 

Lie  between  arrector  muscles  and  hairs. 

^        ,  X-       1  •         i-  J.  f  Palms  of  hands. 

V  ound  over  entire  skin  surface  except  ^  ^  i       f  f    + 

Secrete  sebum,  a  fatty,  oily  substance,  which  keeps  the 
hair  glossy  and  the  skin  flexible,  and  forms  a  protective 
layer  on  surface  of  skin. 

(Modified  sweat-glands. 
Found  in  skin  of  external  auditory  canal. 
Secrete  cerumen,  a  yellow,  pasty  substance,  like  wax. 

Tubular  glands,  consist  of  blind  ends  coiled  in  balls, 
lodged  in  subcutaneous  tissue,  and  surrounded  by  a 
capillary  plexus.  Secrete  sweat  and  discharge  it  by 
means  of  ducts  which  open  exteriorly.     (Pores.) 

Watery,  colorless,  turbid  liquid,  salty  taste,  distinctive 

odor,  and  acid  reaction. 
Consists  of  water,  salts,  fatty  acids,  urea,  and  carbon 

dioxide. 
Average  quantity,  one  quart  in  twenty-four  hours. 
L  Dilute  condition  of  blood. 
2.  Increased  temperature  or  humidity 
of  the  atmosphere. 
Exercise. 
Pain. 

Mental  excitement  or  nervousness. 
Dj'spnoea. 
Use  of  diaphoretics. 


Amount  increased 
by 


3. 
4. 
5. 
6. 
17. 


Chap.  XVIII] 


SUMMARY 


361 


Sweat 


Activity  of 
Sweat- 
glands 


Body  Heat 


Amount  increased 
by 


8.  Csrtain  diseases  • 


Amount  decreased 
by 


Animals     divided 
into  2  classes 


Tuberculosis. 
Acute    rheuma- 
tism. 
Malaria. 
9.  Use    of    electricity    to    stimulate 
secretory  nerves. 
Voiding  a  large  quantity  of  urine. 
Cold. 
Diarrhoea. 
Certain  drugs. 

r  Fevers. 
Certain  diseases  <  Diabetes. 

I  Some  paralyses. 

1.  Direct  stimulation  of  nerve-ending  in  sweat-glands. 

2.  Indirect  stimulation  of  nerve  centres  controlhng  per- 

spiration. 
[  3.  Action  of  vasomotor  nerves  on  calibre  of  blood-vessels. 

1.  Warm-blooded  or  those  which  have 
an  almost  constant  temperature. 

Human  beings  are  in  this  class. 

2.  Cold-blooded  or  those  whose  tem- 
perature varies  with  that  of 
their  environment. 

The  human  foetus  is  cold  blooded. 

1.  Chemical  changes  associated  with 
oxidation. 

2.  Friction  of  muscles,  blood,  etc. 

3.  Ingestion  of  warm  food. 
Wherever  metabohc  changes  are  tak- 
ing place. 

Offers  large  surface  foi 
radiation,  conduction. 
Skin  88  per  j      and    evaporation    of 
cent  I      sweat. 

Contains  large  amount 
Lost  by  \  [of  blood. 

Lungs  —  9  per  cent  is  lost  warming 
the  expired  air  and  the  evaporation 
of  the  water  of  respiration. 
Urine  and  Feces  —  3  per  cent  is  lost 
warming  the  urine  and  feces. 
Distributed  —  by  the  blood  circulating  through  the  blood 
vessels. 

(Heat  centres. 
Sensory  nerves. 
Sweat  nerves. 
[  Vasomotor  nerves. 


Produced  by 


362 


ANATOMY  FOR  NURSES        [Chap.  XVIII 


Body  Heat 


^V 


Regulated 


Variations  in 
Temperature 


Normal 


( Activity  of  sweat-glands. 
Skin  <  Dilatation  and  contraction 

I      of  skin  arterioles. 
Respiration. 
Control  of  metabolism  by  nervous 

system. 
IMuscular  exercise  and  diet. 
Clothing. 

fHot. 
1  Cold. 


2. 
3. 

4. 
5. 

6.  Baths 


Abnormal ' 


1.  Depends  on  where  temperature  is  I  .  ..,. 

taken  |  t^      ' ' 

{ Itectum. 

2.  Depends  on  time  f  Lowest  in  early  morning. 

of  day  I  Highest  in  early  evening. 

3.  Slightly  increased  by  muscular  activitj'  and 

the  digestive  processes. 

4.  Age.    Higher    and  f  Infants,  cliildren,  and 

more  variable  in  I      the  aged. 

Increased  temperature. 
Increased  pulse. 
Symptoms    <  Increased  respiration. 
Increased  tissue  waste. 
Faulty  secretion. 
Cause  —  not  definitely  known. 
Value  —  thought  to  help  the  body  to 
fight  infection. 
Subnormal  —  due  to  diminished  metaboUsm. 


Fever ■ 


CHAPTER  XIX 

THE  NERVOUS   SYSTEM 

In  Chapter  III  it  was  stated  that  eight  systems  of  organs  were 
found  in  the  human  body.  Six  of  these  systems  have  been  studied, 
leaving  the  seventh,  i.e.  the  nervous  system,  to  form  the  subject 
matter  of  this  chapter. 

Parts  of  the  nervous  system.  —  The  nervous  system  consists  of : 
(1)  the  brain  and  spinal  cord,  which  are  contained  within  the 
cavities  of  the  ?kull  and  spinal  column ;  (2)  masses  of  nerve  cell- 
bodies  called  s^Tapathetic  ganglia,  which  are  situated  in  the  head 
and  neck,  also  in  the  thoracic  and  abdominal  cavities ;  (3)  nerve 
trunks,  which  connect  the  brain,  spinal  cord,  and  s;vTnpathetic  gang- 
lia with  each  other,  with  the  viscera,  and  with  the  periphery  of 
the  body.  All  of  these  structures  are  made  up  of  nerve  tissue. 
In  addition  the  endings  of  the  nerves  distributed  to  the  organs 
of  the  special  senses,  such  as  the  eye,  ear,  and  skin,  are  in  close 
contact  with  modified  epithelial  cells  sometimes  called  organules. 

Functions  of  the  nervous  system.  —  The  human  nervous  system 
makes  possible  all  the  higher  functions  of  human  life.  It  enables 
us  to  think  and  to  will,  to  recognize  our  surroundings  and  to 
accommodate  ourselves  to  them ;  to  move,  to  talk,  to  hear,  to  see ; 
and  it  guarantees  equilibrium  and  muscular  coordination. 

Divisions  of  the  nervous  system.  —  For  purposes  of  study  the 
nervous  system  is  arbitrarily  divided  into  two  parts :  (1)  the 
central  nervous  system  or  cerebro-spinal  system,  and  (2)  the 
sympathetic  system.  These  two  systems  are  not  separate,  dis- 
tinct, and  independent  as  the  names  might  imply,  but  are  inti- 
mately connected  both  structurally  and  functionally,  and  are 
really  interdependent. 

(1)  The  central  nervous  system  consists  of  the  brain,  the  spinal 
cord,  and  three  sets  of  nerves. 

(a)  Cerebro-spinal  nerves  connect  the  brain  and  spinal  cord 
and  form  a  part  of  the  cord. 

363 


364  ANATOMY  FOR  NURSES  [Chap.  XIX 

(b)  Cranial  nerves  pass  to  and  from  the  brain  through  openings 
in  or  between  the  cranial  bones,  and  are  distributed  to  various 
organs.     (See  page  395.) 

(c)  Spinal  nerves  pass  to  and  from  the  cord  to  different  parts  of 
the  body.     (See  page  380.) 

(2)  The  sympathetic  system  consists  of  masses  of  nerve  cell- 
bodies,  and  the  nerves  connected  with  them.  These  masses  are 
termed  ganglia  and  are  found  in  the  thoracic  and  abdominal  cavi- 
ties.    (See  page  375.) 

Properties  of  nerve  tissue.  —  All  of  the  organs  included  in  the 
nervous  system  are  made  up  of  nerve  tissue,  which  is  the  most 
highly  specialized  tissue  in  the  body.  It  possesses  the  following 
marked  characteristics:  (1)  irritability  or  the  power  to  respond 
to  stimulation,  and  (2)  conductivity  or  the  power  to  transmit  the 
stimulus  or  nerve  impulse  to  the  muscles,  viscera,  etc.  Just  as  all 
other  tissues  are  composed  of  cells,  so  the  structural  unit  of  nerve 
tissue  is  the  nerve-cell  or  neurone. 

NEURONES 

Although  the  neurones  vary  considerably  in  size  and  in  form, 
there  are  certain  structural  characteristics  which  they  all  possess 
in  common.     They  consist  of  :  — 

(1)  The  cell-body. 

(2)  The  cell-processes. 

These  two  parts  make  up  a  complete  nervous  entity  called  a 
neurone,  and  the  entire  nervous  system  consists  of  neurones 
supported  by  neuroglia^  in  the  central  nervous  system,  and  by  con- 
nective tissue  in  the  nerve  trunks. 

(1)  The  cell-body.  —  The  cell-bodies  vary  as  to  size  and  shape, 
but  all  varieties  present  certain  common  characteristics.  A  topical 
cell-body  consists  of  a  mass  of  granular  cytoplasm  surrounding  a 
large,  well-defined  nucleus,  it  in  turn  containing  a  nucleolus,  and 
the  whole  mass  of  cytoplasm  may  in  some  cases  be  surrounded 
by  a  cell-wall. 

From  the  angles  of  the  cell-body  are  given  off  the  processes  or 

poles,  and  the  number  of  processes  corresponds  to  the  number 

of  angles.     Each  cell-body  usually  has  one  process  and  may  have 

several  more. 

'  See  page  373. 


Chap.  XIX]  THE  NERVOUS  SYSTEM 


365 


wenvE  CELu— — 


^DENOniTES. 


NAKED 
AXIS-CYLINDER. 


-AXIS-CYLINDER   PROCESS. 


COLLATERAL   BRANCH. 


AXIS-CYLINDER 
CLOTHED    WITH 
MEDULLARY      * 
SHEATH. 


—  MEDULLARY   SHEATH. 


— AXIS-CYLIfiOER. 


AXIS-CYLINDER 

CLOTHED     WITH 

MEDULLARY       ■ 

SHEATH     AND 

NEURILEMMA. 


AXIS-CYLINDER         I     || 
CLOTHED     WITH <     ! 


ITH- 
NEURILEMMA. 


—NEURILEMMA, 


NAKED 

Axis-cylinder. 


/ 


TERMINAL   BRANCHES. 


Fig.  175.  —  A  Neurone.     (Gcrrish.) 


366  ANATOMY  FOR  NURSES  [Chap.  XIX 

If  the  cell  has  but  one  process,  that  one  is  the  axis  cylinder  pro- 
cess, and  the  cell  is  spoken  of  as  a  unipolar  cell.  If  the  cell  has  two 
processes,  one  is  the  axis  cylinder  process,  and  the  cell  is  called 
bipolar ;   many  processes,  multipolar. 

Function  of  the  cell-body.  —  The  cell-body  affords  nutriment 
to  its  processes,  as  is  proven  by  the  fact  that  if  a  nerve-fibre  is  cut, 
the  part  separated  from  the  cell-body  dies.  It  also  bears  the  same 
relation  to  the  cell  that  the  battery  does  to  many  kinds  of  electrical 
apparatus:  (1)  it  is  the  centre  in  which  the  action  takes  place 
which  gives  rise  to  nervous  impulses ;  (2)  the  cell-bodies  are  ca- 
pable of  modifying  impulses  brought  to  them  by  their  sensory 
processes.  This  modification  may  take  the  form  of  inhibition  and 
either  partially  or  completely  block  impulses ;  or  it  may  take  the 
form  of  summation,  i.e.  collect  weak  impulses,  and  combine  them 
into  one  effecti^'e  impulse  before  transmission  to  the  motor  nerves. 
As  cell-bodies  are  found  only  in  the  brain,  spinal  cord,  and  ganglia, 
it  is  only  in  these  parts  of  the  nervous  system  that  these  activities 
can  take  place. 

(2)  The  cell-processes.  —  The  cell-processes  are  named  as  fol- 
lows :  — 

(a)  Dendrites  or  dendrons. 

(6)  Axis  cylinder  processes,  named  also  neuraxones,  or  axones. 
fMedullated. 
i^on-medullated. 

(d)  Collaterals. 

(e)  Nerve-endings. 

(«)  Dendrites.  —  These  processes  are  usually  short,  and  rather 
thick  at  their  attachment  to  the  cell-body.  They  have  a  rough 
outline,  diminish  in  calibre  as  they  extend  further  from  the  cell- 
body,  and  branch  rapidly  in  a  tree-like  manner.  These  branches 
are  called  arborizations.     The  number  of  dendrites  varies. 

Function.  —  The  essential  function  of  a  dendrite  is  conduction 
of  a  nerve-impulse  from  the  periphery  to  the  cell-body.  They 
collect  nerve-impulses  from  the  processes  of  other  cells,  and  carry 
them  always  in  one  direction,  i.e.  to  the  cell-body. 

Synapse.  —  In  this  connection  it  is  important  to  emphasize 
that  there  is  no  true  anastomosis  of  processes  from  different  cells. 
The  arborizations  interlace  and  intermingle  so  that  the  nerve- 
impulse  from  one  cell-process  is  able  to  bridge  the  gap  and  set  up 


(c)  Nerve-fibres  j  ^7 


Chap.  XIX]  THE  NERVOUS  SYSTEM  367 

nerve-impulses  in  the  contiguous  process.     This  intermingling  of 
arborizations  is  called  a  synapse. 

(6)  Axis  cylinder  process.  —  There  is  but  one  axis  cylinder 
process  given  off  from  each  cell,  and  it  differs  from  the  dendrites 
in  the  following  particulars :  — 

(1)  It  is  usually  longer;  in  some  instances  it  travels  as  much 
as  39.37  in.  (1  meter)  before  breaking  up  into  its  terminal  branches. 

(2)  It  has  a  smooth  outline  and  diminishes  in  calibre  very 
little. 

(3)  It  gives  off  minute  side  branches  called  collaterals.  These 
are  generally  given  off  at  right  angles  to  the  axis  cylinder. 

(4)  It  merges  into  a  nerve-fibre  and  usually  becomes  enveloped 
in  one  or  two  coats. 

Function.  —  The  function  of  the  axis  cylinder  process  differs 
from  that  of  the  dendrites.  The  dendrites  convey  impulses  to 
the  cell-body,  and  the  axis  cylinder  process  conveys  impulses  from 
the  cell-body.  Some  writers  consider  that  the  axis  cylinder  is 
capable  of  carrying  impulses  in  either  direction,  but  this  is  not  the 
generally  accepted  view. 

(c)  Nerve-fibre.  —  While  the  nerve-fibre  is  really  only  the  con- 
tinuation of  the  axis  cylinder  process  that  has  undergone  some 
change  in  structure,  it  is  advisable  to  describe  the  nerve-fibre 
separately  as  though  it  were  a  new  subject. 

Nerve-fibres  are  of  two  kinds :  medullated,  or  white  fibres,  and 
non-medullated,  or  gray  fibres. 

Medullated  fibre.  —  If  one  looks  at  a  medullated  nerve-fibre 
under  the  microscope,  it  is  found  to  consist  of  three  parts : 
(1)  a  central  core  called  the  axis  cylinder  which  is  a  continuation  of 
the  axis  cylinder  process ;  (2)  immediately  surrounding  the  axis 
cylinder  is  a  sheath,  or  covering,  of  a  semi-fluid,  fatty  substance 
called  the  medullary,  or  myelin,  sheath.  It  is  to  the  refraction  of 
light  from  this  fatty  substance  that  medullated  nerve-fibres  owe 
their  white  color ;  (3)  external  to  the  medullary  sheath  is  a  thin 
membrane  completely  enveloping  the  nerve-fibre  and  forming 
the  outer  covering  called  the  neurilemma.  This  is  comparable 
to  the  sarcolemma  that  invests  muscle-fibres. 

Function  of  the  medullary  sheath.  —  It  is  supposed  that  the 
medullary  sheath  serves:  (1)  as  a  source  of  nourishment,  (2)  as  a 
protection,  and   (3)  as  a  non-conducting  medium  for  the  axis 


368  ANATOMY   FOR   NURSES  [Chap.  XIX 

cylinder.  In  the  last-mentioned  capacity  it  is  thought  that  this 
sheath  prevents  the  deflection  of  nerve-impulses  from  their  in- 
tended course,  in  some  such  way  as  the  insulation  on  an  electric 
wire  prevents  the  current  from  taking  a  path  other  than  the  one 
desired. 

Nodes  of  Ranvier.  —  At  regular  intervals  along  the  course  of  a 
meduUated  nerve-fibre  there  are  noted  ring-like  constrictions 
about  the  nerve-fibre  dividing  the  nerve-fibre  into  a  series  of 
links.     These  constrictions  are  the  nodes  of  Ranvier. 

At  each  node  the  constriction  is  due  to  a  loss  of  continuity  or 
absence  of  the  medullary  sheath,  thus  allowing  the  neurilemma  to 
dip  in,  so  to  speak,  and  come  in  direct  contact  with  the  axis  cylin- 
der. Thus  at  each  node  the  nerve-fibre  is  smaller  in  diameter, 
this  change  in  diameter  being  entirely  at  the  expense  of  the  medul- 
lary sheath,  the  axis  cylinder  being  unchanged.  These  nodes  are 
about  1  mm.  apart,  and  the  portion  between  two  consecutive  nerves 
is  called  a  nerve  segment.  If  a  nerve-fibre  divides,  the  division 
occurs  at  one  of  these  nodes.  In  each  nerve  segment  the  neuri- 
lemma is  seen  to  have  a  nucleus.  MeduUated  nerve-fibres  may  be 
very  long,  but  the  diameter  is  very  minute. 

Function  of  the  nodes  of  Ranvier.  —  The  passage  of  the  blood- 
plasma  into  the  axis  cylinder  is  rendered  easier  by  the  absence  of 
the  medullary  sheath  at  the  nodes  of  Ranvier,  and  this  is  thought 
to  be  their  function. 

Non-medullated  fibre.  —  Non-medullated  nerve-fibres  or,  as 
they  are  sometimes  called,  the  fibres  of  Remak,  do  not  differ  in 
any  respect  from  the  meduUated  nerve-fibres  save  in  the  absence 
of  the  medullary  sheath,  the  axis  cylinder  being  directly  invested 
by  the  neurilemma.  Owing  to  the  absence  of  the  refracting 
medium  (the  medullary  sheath),  the  non-medullated  fibres  do 
not  appear  white,  but  present  a  grayish  or  yellow  color. 

(d)  Collaterals.  —  The  minute  side  branches  given  off  at  right 
angles  from  the  axis  cylinder  process  are  called  collaterals.  These 
are  found  chiefly  in  the  brain,  spinal  cord,  and  ganglia.  They  end 
either  in  bulbous  enlargements,  or  in  fine  brush-like  terminations, 
which  come  in  contact  (synapse)  with  the  processes  from  other 
neurones. 

(e)  Nerve-endings.  —  Nerve-endings  may  be  classified  accord- 
ing to  the  part  of  the  body  in  which  they  are  found. 


Chap.  XIX]  THE   NERVOUS  SYSTEM  369 

1.  Nerve-fibres   which   terminate  in  the  brain  or  spinal  cord 
split  up  into  end  arborizations. 

2.  Sensory  nerve-fibres  ending  at  the  periphery  of  the  body 
terminate  in  two  ways  :  — 

(a)  Inter-epithelial  arborizations. 

(b)  Organules. 

3.  Motor  nerve-fibres  ending  in  voluntary  muscles  terminate  in 
motor  plates. 

4.  JNIotor  nerve-fibres  ending  in  involuntary  muscles  (such  as  in 
the  viscera)  terminate  in  a  plexus. 

End  arborizations.  —  If  the  nerve-fibre  is  to  terminate  while 
still  lying  in  the  mass  of  the  nervous  system,  its  axis  cylinder  may 


Fig.  176.  —  Sensory  Nerve   Terminations  in  Stratified  Pavement  Epi- 
thelium.    (Kirkes.) 

split  up  at  the  termination  into  a  number  of  short  filaments  called 
end  arborizations,  which  interlock  with  the  dendrites  of  another 
neurone,  or  the  axis  cylinder  may  send  out  collaterals  which  inter- 
lock with  dendrites.  Thus  an  individual  neurone  would  serve  only 
as  a  relay  station. 

Inter-epithelial  arborizations.  —  This  is  the  most  common  mode 
of  termination  of  sensory  nerves.  The  nerve-fibres  pass  to  the 
surface  either  in  the  skin  or  mucous  membrane ;  the  neurilemma 
and  medullary  sheath  disappear,  the  naked  axis  cylinder  subdivid- 
ing into  minute  arborizations  that  ramify  between  the  epithe- 
lial cells  of  the  surface  of  the  body.  This  method  is  the  one  in 
which  nerves  terminate  in  various  glands,  hairs,  teeth,  tendons,  etc. 

Organules.  —  Some  of  the  highly  complex  special  sensations 
need  very  complex  end  organs  for  their  reception.  These  end  or- 
gans are  modified  epithelial  cells  and  are  called  organules.  The 
axis  cylinder  subdivides  into  arborizations  as  described  above; 
2b 


370 


ANATOMY  FOR   NURSES 


[Chap.  XIX 


and  these  enter  and  terminate  in  the  organules.  The  different 
varieties  of  tactile  corpuscles,  the  organ  of  Corti,  for  the  auditory 
nerve,  and  the  rods  and  cones  of  the  retina 
may  be  cited  as  examples  of  organules. 

Motor  plates.  —  A  nerve  intended  to 
stimulate  a  muscle  to  activity  terminates 
by  a  subdivision  of  the  axis  cylinder  (the 
neurilemma  and  medullary  sheath  fading 
out),  each  branch  of  the  axis  cylinder  end- 
ing in  a  flat  nodule  of  granular  material 
lying  on  the  muscle  fibre.  This  terminal 
mass  is  the  motor  plate. 

Plexus.  —  The  nerve-fibres  which  are 
distributed  to  the  viscera  are  non-medul- 
lated,  antl  near  their  terminations  each  one 
divides  into  a  number  of  branches  which 
arborize  with  each  other  and  form  a  net- 
work or  plexus.  From  this  plexus  smaller 
branches  are  given  off,  these  subdivide  to 
form  fibrils,  and  the  fibrils  terminate  on  the 
surface  of  the  muscle  cells.  (See  page 
377.) 

Nature  of  nerve-impulse.  —  Having  ex- 
amined the  make-uj)  of  a  complete  ner- 
vous entity  (the  neurone),  it  now  seems 
best  to  study  the  nature  of  nerve-impulses. 
The  nature  of  a  nerve-impulse  is  not  known.  We  know  that 
nerve-fibres  may  be  stimulated  by  several  means,  and  the  practical 
result  is  similar  to  the  result  obtained  were  the  nerve  stimulated 
by  the  natural  physiological  impulse.  The  nerve-fibre  has  no 
power  to  initiate  a  nerve-impulse,  but  serves  merely  as  a  conveyor 
of  the  impulse  which  has  been  started  either  in  the  end  organs  or 
in  the  nerve-cell. 

Artificial  nerve  stimulation.  —  There  are  four  means  usually 
applied  to  the  artificial  stimulation  of  a  nerve-fibre,  viz. : 
chemical,  thermal,  mechanical,  and  electrical,  —  the  latter  the 
most  usual.  That  the  true  physiological  impulse  is  none  of 
these  can  be  readily  proven.  (See  any  standard  work  of  physi- 
ology.), 


Fig.  177. —  Pacini's  Cor- 
puscle, a,  stalk;  b,  nerve- 
fibre  entering  it ;  a,  d,  con- 
nective-tissue envrlope ;  e, 
axis  cylinder,  with  its  end 
divided  at  /.      (Collins.) 


Chap.  XIX]  THE   NERVOUS   SYSTEM  371 

Physiological  nerve  stimulation.  —  The  best  explanation  is 
that  the  true  nature  of  nerve-impulse  is  a  physical  molecular 
vibration  set  up  either  in  the  nerve-cell  or  the  end  organs  and 
transmitted  along  the  nerve-fibre. 

Direction  of  nerve-impulse.  —  Within  the  body  nerve-impulses 
travel  in  two  directions :  (1)  from  the  cell-body  to  the  periphery, 
and  (2)  from  the  periphery  to  the  cell-body. 

Afferent  and  efferent  nerve-fibres.  —  From  the  previous  para- 
graph it  is  deduced  that  the  nerve-fibres  are  divided  into  two  great 
classes :  (1)  efferent  or  centrifugal  are  those  in  which  the  direc- 
tion for  the  nerve-impulses  to  travel  is  from  the  cell-body  to  the 
periphery;  and  (2)  afferent  or  centripetal  are  those  in  which 
the  impulses  travel  from  the  periphery  to  the  cell-body. 

The  most  striking  example  of  efferent  fibres  are  those  which 
convey  impulses  that  stimulate  functional  activity,  i.e.  muscular 
contraction  or  glandular  secretion ;  hence  the  efferent  nerve- 
fibres  are  often  spoken  of  as  motor,  although  motion  is  the  mani- 
festation of  but  a  class  of  neurones.  On  the  other  hand,  afferent 
fibres  are  often  spoken  of  as  sensory,  because  it  is  to  them  that 
sensation  is  due. 

Reason  for  direction  of  nerve-impulse.  —  Normally  the  efferent 
fibres  are  stimulated  only  through  the  cell-bodies  from  which 
they  spring,  and  the  afferent  fibres  are  stimulated  only  at  their 
endings.  For  this  reason  a  nerve-fibre  can  carry  impulses  only 
in  one  direction. 

Classification  of  nerve-fibres.  —  In  addition  to  classifying  nerve- 
fibres  as  efferent  and  afferent,  we  may  subdivide  peripheral  nerve- 
fibres  into  smaller  groups  depending  upon  their  physiological  dif- 
ferences. Numerous  experiments  have  demonstrated  that  the 
effect  of  an  impulse  conveyed  by  nerve-fibres  may  be  either  excita- 
tory or  inhibitory;  i.e.  the  tissue  or  cell  may  be  stimulated  to 
activity,  or  if  already  in  activity  it  may  be  reduced  to  a  condition 
of  rest.  On  this  basis  both  afferent  and  efferent  fibres  may  be 
subdivided  into  excitatory  and  inhibitory  fibres.  Each  of  these 
subgroups  may  be  further  divided  according  to  the  kind  of  activity 
it  excites  or  inhibits,  and  according  to  the  kind  of  muscle  or  tissue 
in  which  it  ends.  The  following  classification,  taken  from  "  Text- 
book of  Physiology,"  by  William  H.  Howell,  depends  upon  three 
principles  :  (1)  the  direction  in  which  the  impulse  travels  normally ; 


372 


ANATOMY  FOR   NURSES  [Chap.  XIX 


(2)  whether  this  impulse  excites  or  inhibits ;  and  (3)  the  kind  of 
action  excited  or  inhibited,  which  in  turn  depends  upon  the  kind 
of  tissue  in  which  the  fibres  end. 


Eflferent 


Excitatory- 


Inhibitory 


Motor 


Secretory 


Inhibito-motor 
Inhibito-secre-  < 
tory 


Motor. 
Vasomotor. 
Cardiomotor. 
Visceromotor. 
Pilomotor. 
Salivary. 
Gastric. 
I  Pancreatic. 
I  Sweat. 
Subdivisions  corresponding  to  the 

varieties  of  motor  fibres  above. 
Subdivisions     corresponding     to 

the  varieties  of  secretory  fibres 

above. 


Afferent  < 


Excitatory 


Sensory 


Inhibitory 


Reflex 


Inhibito-reflex 


Visual. 

Auditor}'. 

Olfactory. 

Gustatory. 

Pressure. 

Temperature. 

Pain. 

Hunger. 
.  Thirst,  etc. 

I  According  to   the  efferent  fibres 
I      affected. 

Inhibitory  effects  upon  the  con- 
scious sensations  are  not  de- 
monstrated. 

The  reflex  fibres  that  cause  un- 
conscious reflexes  are  known  to 
be  inhibited  in  some  cases  at 
least. 


Identity  of  nerve-impulses.  —  The  generally  accepted  belief 
is  that  nerve-impulses  are  identical  in  character  and  vary  only  in 
intensity.  According  to  this  the  impulses  carried  by  a  sensory 
nerve  are  similar  in  character  to  those  carried  by  a  motor  nerve, 
and  yet  the  result  is  different.  The  result  is  thought  to  be  deter- 
mined by  the  nature  of  the  tissue  in  which  a  nerve-fibre  ends, 
rather  than  by  the  nature  of  the  fibre  itself. 


Chap.  XIX]  THE   NERVOUS   SYSTEM  373 

Speed  of  nerve-impulses.  —  The  speed  at  which  an  impulse 
travels  along  an  afferent  nerve-fibre  is  found  to  be  about  140 
feet  (42.6  m.)  per  second.  The  efferent  impulses  travel  some- 
what slower,  110  feet  (33.5  m.)  per  second. 

It  may  be  interesting  to  note  how  very  slow  a  nerve-impulse 
is  when  compared  with  light  which  travels  at  the  rate  of  about 
186,000  miles  per  second,  and  sound  which  travels  about  1100 
feet  per  second. 

Reaction  of  nerve-endings.  —  A  study  of  the  previous  classifica- 
tion shows  that  the  sensory  nerve-endings  are  not  all  affected  by 
the  same  stimulus,  nor  do  they  react  in  the  same  way.  Thus 
some  of  the  sensory  nerve-endings  are  affected  by  pressure,  and 
others  by  temperature.  The  endings  of  the  auditory  nerve  in  the 
ear  are  affected  only  by  sound,  and  the  endings  of  the  optic  nerve 
in  the  eye  are  affected  by  ligh.:,  though  a  similar  effect  may  be 
produced  by  a  blow  on  the  head,  or  an  accident  which  jars  the 
spinal  column. 

Gray  matter.  —  The  cell-bodies,  dendrites,  commencement  of 
the  axis-cylinder  processes,  and  their  collaterals  are  not  scattered 
promiscuously  throughout  the  body,  but  are  gathered  together  in 
certain  definite  regions  or  groups.  These  form  the  gray  matter 
of  the  brain,  spinal  cord,  and  ganglia. 

White  matter.  —  The  white  matter  consists  of  medullated  nerve- 
fibres  and  is  found  in  the  brain,  spinal  cord,  ganglia,  and  also 
in  the  nerve  trunks  distributed  to  all  parts  of  the  body. 

Neuroglia.  —  Neuroglia  is  not  nervous  tissue,  but  is  a  special 
kind  of  tissue  found  in  the  brain  and  spinal  cord,  and  serves 
the  same  purpose  as  connective  tissue  in  other  parts  of  the  body. 
It  consists  of  cells  that  give  off  many  fine  processes  which  extend 
in  every  direction  and  form  a  supporting  and  connecting  network 
among  the  nerve-cells,  nerve-fibres,  and  blood-vessels. 

Formation  of  nerve-trunks.  —  The  nerve-fibre  of  each  neurone 
is,  as  has  been  described,  of  microscopic  diameter,  but  when 
a  number  of  these  nerve-fibres  are  bound  together  in  a  bundle  we 
have  the  plainly  visible  nerve-trunks,  or  nerves,  such  as  are  seen  in 
dissections  of  the  body. 

Nerves  are  whitish  cords  which  extend  between  cells  situated 
in  different  parts  of  the  brain,  spinal  cord,  and  ganglia,  also  between 
these  centres  and  all  parts  of  the  body.     They  thus  afford  a  means 


374 


ANATOMY  FOR  NURSES  [Chap.  XIX 


of  communication  between  :   (1)  the  different  parts  of  the  nervous 
system,  (2)  the  nerve  centres  and  the  viscera,  (3)  the  nerve  centres 

and  the  periphery,  and  (4) 
the  viscera  and  the  surface 
of  the  body. 

Between  the  nerve- 
fibres  is  a  small  amount 
of  connective  tissue  which 
serves  not  only  to  bind 
the  fibres  together  into 
bundles,  or  funiculi,  but 
also  to  carry  to  or  from 
the  fibres  the  blood-vessels 
and  the  lymphatics  nec- 
essary for  their  imtrition. 
Connective  tissue  also 
surrounds  these  bundles 
in  the  form  of  a  sheath. 

Although  the  nerves 
branch  frequently  through- 
out their  course,  and  these 
branches  often  meet  and 
fuse  with  one  another,  or 
with  the  branches  of  other 
nerves,  yet  each  nerve- 
fibre  always  remains  quite 
distinct,  never  branching 
until  it  reaches  its  ter- 
mination, and  never  unit- 
ing with  other  nerve-fibres. 
The  nerve-trunk  is  thus  merely  an  association  of  individual 
fibres  which  have  very  difTerent  activities  and  which  may  func- 
tion entirely  independent  of  one  another.  Perhaps  the  best  idea 
of  the  arrangement  of  ner\'e-fibres  in  a  trunk  can  be  obtained  from 
a  cross-section  of  a  nerve  such  as  is  seen  in  Figure  179. 

Nerve  centres.  —  Groups  of  nerve-cells  exercising  control  over 
some  definite  function  are  called  centres.  Each  of  these  centres 
is  influenced  by  impulses  from  various  parts  of  the  body  which 
travel  along  special  nerves  to  these  centres.     Many  of  these  cen- 


FiG.     178.  —  Diagram 
General    Arrangement    of 
SPINAL  System. 


ILLUSTRATING      THE 
THE     CeREBRO- 


Chap.  XIX] 


THE  NERVOUS  SYSTEM 


375 


tres  are  situated  in  the  medulla  and  spinal  cord.  Most  of  the  cen- 
tres in  the  medulla  are  concerned  with  processes  that  are  absolutely 
necessary  to  life,  hence  are  called  vital  centres.  Examples  of  these 
are  the  centres  controlling  respiration  and  the  cardiac  centre. 

Intercentral  neurones  and  relays.  —  Neurones  whose  processes 
do  not  pass  outside  of  the  brain  or  spinal  cord  are  called  intercentral 
or  connecting  neurones.  An  impulse  passing  from  say  the  foot 
to  the  brain,  might  have  to  pass  through  two  or  three,  or  even 


Fig.  179.  —  Transverse  Section  of  the  Sciatic  Nerve  of  Cat  about  X  100. 
—  It  consists  of  bundles  (funiculi)  of  nerve-fibers  ensheathed  in  a  fibrous  supporting 
capsule. 

more,  neurones ;  these  neurones  form  a  system  of  relays.  A  par- 
allel may  be  found  in  sending  a  telegraphic  message ;  the  message 
may  have  to  pass  over  several  different  systems  of  wires  and  even- 
tually be  carried  by  messenger  before  it  reaches  its  destination. 
These  relays  only  occur  in  the  brain  and  spinal  cord.  In  the  illus- 
tration referred  to  above,  one  relay  would  take  the  impulse  to  the 
spinal  cord ;  this  naturally  means  a  very  long  fibre  ;  one  or  several 
might  be  required  to  take  it  from  the  spinal  cord  to  the  brain. 


THE   SYMPATHETIC   SYSTEM 

The  sympathetic  system  consists  of  three  sets  of  ganglia  and  the 
nerves  connected  with  them  :  — 

1.  Vertebral  or  lateral  ganglia. 

2.  Collateral  or  prevertebral  ganglia,  and  plexuses. 

3.  Terminal  ganglia  and  plexuses. 

4.  Sympathetic  ganglia  in  the  brain  and  cord. 


376  ANATOMY  FOR  NURSES  [Chap.  XIX 

The  vertebral  ganglia.  —  The  vertebral  ganglia  consist  of  a 
chain  of  ganglia  situated  on  each  side  of  the  spinal  column,  and 
extending  from  the  base  of  the  skull  to  the  cocc^'x.  There  are 
about  forty-nine  of  these  ganglia,  twenty-four  on  each  side  of  the 
spine,  and  one  in  front  of  the  coccyx.  They  are  connected  with 
each  other  by  nerve-fibres  called  ganglia  cords,  and  with  the  spinal 
nerves  by  branches  which  are  called  rami  communicantes}  They 
are  also  connected  to  the  viscera  and  blood-vessels  by  branches 
which  travel  different  pathways:  (1)  they  pass  directly  to  the 
viscera ;  (2)  they  converge  to  form  three  main  nerve-trunks, 
called  the  great  splanchnic,  the  small  splanchnic,  and  the  least 
splanchnic,  and  then  send  branches  from  these  trunks  to  the  vis- 
cera ;  (3)  they  join  the  collateral  ganglia  and  plexuses ;  (4)  they 
join  the  spinal  nerves,  and  in  them  reach  the  part  of  the  body  for 
which  they  were  destined. 

The  collateral  ganglia.  —  The  collateral  or  outlying  ganglia 
consist  of  masses  of  gray  matter  and  their  nerves,  which  are  located 
principally  in  the  thoracic  and  abdominal  cavities.  They  are 
connected  with  the  spinal  nerves,  with  the  vertebral  ganglia,  and 
send  branches  to  the  viscera.  These  branches  form  plexuses,  the 
most  important  of  which  are  :  (1)  the  cardiac  plexus,  located  above 
the  heart  and  supplying  it  with  sympathetic  fibres,  (2)  the  solar 
plexus,  located  behind  the  stomach  and  supplying  most  of  the  ab- 
dominal viscera,  (3)  the  hypogastric  or  pelvic  plexus,  located  in  the 
lower  part  of  the  abdomen  and  supplying  the  viscera  of  the  pelvis. 

The  terminal  ganglia.  —  The  terminal  ganglia  include  all  the 
ganglia  situated  in  the  walls  of  the  organs  themselves,  as  for  in- 
stance those  in  the  walls  of  the  heart,  and  in  the  walls  of  the  ali- 
mentary canal.  These  ganglia  are  directly  connected  with  the 
collateral  ganglia,  and  in  some  instances  the  nerves  derived  from 
the  collateral  plexuses  form  a  secondary  or  terminal  plexus  on  the 
organs. 

Sympathetic  ganglia  in  the  brain  and  spinal  cord.  —  In  connec- 
tion with  a  few  of  the  cranial  nerves,  such  as  the  third  and  fifth, 
certain  ganglia  are  found.  Sympathetic  ganglia  are  also  found 
in  the  spinal  canal  and  in  the  medulla.  (See  vasomotor  centres.)  ^ 
Autonomic  system  is  a  name  that  has  recently  been  suggested  for 
the  sympathetic  system  as  outlined  above.     Prior  to  the  introduc- 

» See  page  377.  «  See  page  378. 


Chap.  XIX]  THE  NERVOUS  SYSTEM  377 

tion  of  this  name,  the  fourth  group  was  not  included  in  the  sym- 
pathetic system.  The  term  autonomic  impHes  that  these  nerves 
are  to  some  extent  independent  of  the  central  nervous  system  and 
possess  a  certain  amount  of  self-government. 

Rami  communicantes.  —  The  nerve-fibres  that  connect  the 
vertebral  ganglia  and  the  spinal  nerves  are  called  rami  communi- 
cantes. Each  connection  consists  of  two  rami,  one  white  and  the 
other  gray.  The  white  ramus  consists  of  medullated  fibres,  and 
these  pass  from  the  cord  to  the  ganglion.  The  gray  ramus  consists 
of  non-medullated  fibres  that  pass  from  the  ganglion  to  join  the 
spinal  nerve. 

Plexuses.  —  The  term  plexus  has  been  used  to  designate  a  net- 
work of  nerves.  It  is  worthy  of  special  mention  because  the  nerve- 
fibres  arborize  with  each  other,  and  there  is  an  interchange  of  fibres 
between  the  different  nerve-trunks.  The  advantages  of  this  ar- 
rangement are :  (1)  each  nerve  is  less  dependent  on  the  unimpaired 
condition  of  any  single  portion  of  the  nerve-trunk  or  nerve-centre, 

(2)  each  nerve  has  a  wider  communication  with  the  nerve-centres, 
and  (3)  any  given  part  of  the  body  is  not  dependent  on  one  nerve. 
The  various  plexuses  of  the  sympathetic  system  serve  all  these 
purposes,  and  in  addition  the  organs  constituting  any  one  system 
are  brought  into  direct  communication  with  each  other.  In  this 
way  coordination  of  action  is  secured. 

Distribution  of  sympathetic  nerves.  —  Nerve-fibres  from  the 
sympathetic  system  are  distributed:  (1)  to  the  heart,  (2)  to  the 
involuntary  muscles  of  the  blood-vessels,  lymphatics,  and  viscera, 

(3)  to  the  secretory  glands,  and  (4)  to  some  of  the  special  senses, 
such  as  those  that  regulate  the  pupil  of  the  eye. 

Interdependence  of  the  sympathetic  and  central  nervous  sys- 
tems. —  The  fibres  which  connect  the  s^^mpathetic  ganglia  and  the 
spinal  nerves  form  a  direct  pathway  for  impulses  from  all  of  the 
viscera  to  the  spinal  cord  and  brain.  In  addition  many  of  the 
viscera  are  connected  with  the  brain  by  the  cranial  nerves  (see 
page  395).  This  means  that  there  are  often  two  sets  of  nerve-fibres 
distributed  to  an  organ,  and  we  know  that  in  some  instances  the 
action  of  these  fibres  is  antagonistic.  This  is  true  in  the  case  of  the 
inhibitory  and  accelerator  fibres  of  the  heart,  and  increased  knowl- 
edge may  prove  it  to  be  true  in  connection  with  all  the  organs  of  the 
body. 


378.  ANATOMY  FOR  NURSES  [Chap.  XIX 

Vasomotor  centres.  —  The  chief  vasomotor  centres  are  situated 
in  the  medulla  oblongata,  but  there  are  also  subsidiary  centres  in 
the  spinal  cord.  The  vasomotor  nerves  are  of  two  kinds,  —  vaso- 
constrictor and  vaso-dilator.  While  these  nerves  are  always 
considered  as  belongino;  to  the  sympathetic  system,  it  should  be 
noted  that  the  centre  that  controls  them  is  located  in  the  medulla, 
which  is  part  of  the  central  nervous  system. 

SPINAL  CORD 

The  spinal  cord  is  that  portion  of  the  nervous  system  lodged 
within  the  spinal  canal  of  the  vertebral  column.  It  consists  of  a 
collection  of  gray  and  white  substance,  extending  from  the  foramen 
magnum  of  the  skull,  where  it  is  continuous  with  the  medulla 
oblongata  of  the  brain,  to  about  the  second  lumbar  vertebra,  where 
it  tapers  off  into  a  fine  thread.  Before  its  termination  it  gives  off 
a  number  of  fibres  which  form  a  tail-like  expansion,  called  the 
Cauda  equina. 

Membranes  of  the  cord.  —  Like  the  brain,  the  spinal  cord  is 
protected  and  nourished  by  three  membranes.  These  membranes 
have  the  same  names  and  practically  exercise  the  same  functions 
as  those  enveloping  the  brain  (for  description  of  which  see  page 
384).  The  outer  membrane  is  not  attached  to  the  walls  of  the 
spinal  canal,  being  separated  from  them  by  a  certain  quantity 
or  areolar  and  adipose  tissue,  and  a  network  of  veins. 

Structure  of  the  cord.  —  The  spinal  cord  does  not  fit  closely 
into  the  spinal  canal,  as  the  brain  does  in  the  cranial  cavity, 
but  is,  as  it  were,  suspended  within  it.  It  diminishes  slightly  in 
size  from  above  downward,  with  the  exception  of  presenting  two 
enlargements  in  the  cervical  and  lumbar  regions,  where  the 
nerves  are  given  off  to  the  arms  and  legs  respectively.  It  is 
usually  from  sixteen  to  seventeen  inches  (400  to  425  mm.)  long, 
and  has  an  average  diameter  of  three-fourths  of  an  inch  (19  mm.). 
The  spinal  cord  is  almost  completely  divided  into  lateral  halves 
by  an  anterior  and  posterior  fissure,  the  anterior  fissure  dividing 
it  in  the  middle  line  in  front,  and  the  posterior  fissure  in  the  middle 
line  behind.  In  consequence  of  the  presence  of  these  fissures, 
only  a  narrow  bridge  of  the  substance  of  the  cord  connects  its  two 
halves.  This  bridge,  also  called  isthmus,  is  traversed  throughout 
its  entire  length  by  a  minute  central  canal.     On  making  a  trans- 


Chap.  XIX] 


THE  NERVOUS   SYSTEM 


379 


verse  section  of  the  spinal  cord,  the  gray  matter  is  seen  to  be  ar- 
ranged in  the  form  of  a  butterfly  with  extended  wings.  The  tips 
of  each  wing  are  called  its  horns  or  cornua,  the  anterior  horns  being 
thicker  and  larger  than  the  posterior.  The  transverse  bar  of  gray 
matter  found  in  the  isthmus  is  called  the  gr^y  commissure,  and  it 
connects  the  two  lateral  masses  of  gray  matter.  The  white  matter 
is  arranged  around  and  between  the  gray  matter,  tne  proportion 
of  gray  and  white  varying  in  different  regions  of  the  cord.     The 


VCNTRO-MCDIAN 
FISSURE 


VENTRAL   ROOTS 


VENTRAL  HORN 


LATERAL  HORN 


RETICULAR 


OORSAL    HORN 


OORSO-LATERAL 
FISSURE 


OORSAL  ROOTS 


OORSO-MEOIAN 
FISSURE 


Fig.  180.  —  Transverse  Section  of  the  Spinal  Cord  at  the  Middle  of 
THE  Thoracic  Region.  The  neuroglia  septum  has  been  removed  from  between 
the  dorsal  columns.     (Gerrish.) 


white  matter  is  composed  of  medullated  nerves,  and  the  gray 
matter  consists  of  cell-bodies,  dendrites,  axis  cylinder  processes, 
and  collaterals,  all  held  together  and  supported  by  neuroglia.  The 
medullated  nerve-fibres  are  grouped  in  bundles  known  as  tracts 
or  columns,  and  the  majority  run  in  a  longitudinal  direction. 
These  tracts  are  classified  under  two  main  headings:  (l)sensory, 
or  those  which  carry  impulses  upward  to  the  brain ;  they  begin 
in  the  gray  matter  of  the  cord,  ascend,  and  terminate  in  the  gray 
matter  of  the  brain ;    (2)  motor,  or  those  which  carry  impulses 


,380  ANATOMY  FOR   NURSES  [Chap.  XIX 

downward ;  they  begin  in  the  gray  matter  of  the  brain,  descend, 
and  terminate  in  the  gray  matter  of  the  cord.  The  most  im- 
portant tracts  are :  — 

Postero  internal  tract  or  Cohimns  of  Goll. 
Ascending  or        Postero  external  tract  or  Columns  of  Burdach. 
Sensory  Antero  lateral  tracts. 

Postero  lateral  tracts. 
Descending  or     f  Crossed  pyramidal  tract. 
Motor  \  Direct  pyramidal  tract. 

In  addition  to  these  long  tracts,  there  are  shorter  columns  con- 
sisting of  both  sensory  and  motor  nerves,  which  serve  to  connect 
centres  at  different  levels  in  the  cord,  and  on  different  sides  of  the 
cord.     These  are  called  lateral  columns. 

SPINAL  NERVES 

There  are  thirty-one  pairs  of  spinal  nerves,  arranged  in  the 
following  groups,  and  named  from  the  region  through  which  they 
pass.     They  are  :  — 

Cervical 8  pairs. 

Thoracic 12  pairs. 

Lumbar 5  pairs. 

Sacral        5  pairs. 

Coccygeal 1  pair. 

The  first  cervical  nerve  arises  from  the  medulla  oblongata  and 
leaves  the  neural  canal  between  the  occipital  bone  and  the  altas. 
With  this  one  exception  the  spinal  nerves  spring  from  both  sides 
of  the  spinal  cord,  and  with  one  exception  —  coccj^geal — they 
pass  out  through  the  intervertebral  foramina.  The  coccyxgeal 
passes  through  the  lower  extremity  of  the  canal. 

Mixed  nerves.  —  The  spinal  nerves  consist  almost  entirely  of 
medullated  nerve-fibres,  and  are  called  mixed  nerves  because  they 
contain  both  sensory  and  motor  fibres.  Each  spinal  nerve  has  two 
roots,  a  ventral  or  anterior  root  and  a  dorsal  or  posterior  root. 
The  fibres  connected  with  these  two  roots  are  collected  into  one 
bundle,  and  form  one  nerve  just  before  leaving  the  canal  through 
the  intervertebral  openings.     Before  joining  to  form  a  common 


Chap.  XIX] 


THE  NERVOUS  SYSTEM 


381 


trunk,  the  fibres  connected  with  the  dorsal  root  present  an  en- 
largement, this  enlargement  being  due  to  a  ganglion,  or  small 
nerve-centre,  situated  in  the  intervertebral  foramina.  The  fibres 
of  the  ventral  root  arise  from  the  gray  matter  in  the  ventral  horn, 
and  are  direct  prolongations  from  the  cell-bodies  there. 

The  fibres  of  the  posterior  root  arise  from  the  cells  composing 
the  enlargement  or  ganglion  of  the  posterior  root  and  pass  toward 
the  periphery ;    each  cell  of  the  ganglion,  besides  sending  toward 


Fig.  181.  —  Diagram  of  Nerve  Roots  emerging  from  Spinal  Cord.  P.R. 
posterior  root.  Sp.G.  ijosterior  root  ganglion.  A.R.  anterior  root.  (Schematic.) 
(Collins.) 


the  periphery  the  nerve-fibres  just  described,  sends  a  branch  along 
the  posterior  root  up  into  the  gray  matter  of  the  posterior 
horn,  there  to  break  up  into  branches  articulating  with  other 
cells  or  dendrites.  All  the  fibres  making  up  the  ventral  root 
are  efferent  fibres,  and  convey  nervous  impulses  from  the  spinal 
cord  to  the  periphery.  The  fibres  making  up  the  dorsal  root 
are  aflFerent  fibres,  and  convey  nervous  impulses  from  the  periph- 
ery to  the  spinal  cord. 

It  should  be  borne  in  mind  that  the  dorsal  roots  contain  only 
sensory  fibres,  and  that  these  fibres  always  have  their  origin 
outside  of  the  cord  (i.e.  in  the  spinal  ganglia),  while  the  ventral 
roots  contain  only  motor  fibres,  and  these  have  their  origin 
within  the  central  nervous  system. 

The  relations  of  the  roots,  fibres,  and  so  forth,  can  be  best 


382 


ANATOMY  FOR  NURSES  [Chap.  XIX 


understood  from  a  study  of  the  accompanying  diagrams  (Figs. 
181  and  182). 

Degeneration  and  regeneration  of  nerves.  —  Since,  as  has  been 
stated,  tlu'  cc'll-hody  is  essential  for  tlie  nutrition  of  the  whole  cell, 
it  follows  that  if  the  processes  of  a  neurone  are  cut  oft",  they  will 
suffer  from  malnutrition  and  die.  If,  for  instance,  a  spinal  nerve 
be  cut,  all  the  peripheral  part  will  die,  since  the  fibres  composing 
it  have  been  cut  oft"  from  their  cell-bodies  situated  in  the  cord,  or  in 
the  spinal  ganglia.  The  divided  ends  of  a  nerve  that  has  been  cut 
across  readily  reunite  by  cicatricial  tissue,  —  that  is  to  say,  the 
connective  tissue  framework  unites,  but  the  cut  ends  of  tlie  fibres 
themselves  do  not  unite.  On  the  contrary,  the  peripheral  or 
severed  portion  of  the  nerve  begins  to  degenerate,  the  medullary 


Fig.  182.  —  Degeneration  of  Spinal  Nerves  and  Nerve-roots  after 
Section.  A,  section  of  ncrvo-trunk  beyond  the  ganglion;  B,  section  of  anterior 
root ;  C,  section  of  posterior  root ;  D,  excision  of  ganglion ;  a,  anterior  root ;  p, 
posterior  root ;  g,  ganglion. 


sheath  breaks  up  into  a  mass  of  fatty  molecules  and  is  gradually 
absorbed,  and  finally  the  axis  cylinder  also  disappears.  In  regen- 
eration, the  new  fibres  grow  afresh  from  the  axis  cylinder  of  the 
central  end  of  the  severed  nerve-trunk,  and  penetrating  into  the 
peripheral  end  of  the  neurilemma,  grow  along  this  as  the  axis 
cylinder  of  the  new  nerve,  each  axis  cylinder  becoming  after  a  time 
surrounded  with  a  medullary  sheath.  Restoration  of  function  in 
the  nerve  may  not  occur  for  several  months,  during  which  time  it  is 
presumed  the  new  nerve-fibres  are  slowly  finding  their  way  along 
the  course  of  those  which  have  been  destroyed. 

Distribution  of  the  terminal  branches  of  the  spinal  nerves.  — 
After  leaving  the  spinal  canal  each  spinal  nerve  divides  into  two 
main  trunks  known  as  the  anterior  and  posterior  divisions.  Each 
of  these  contain  sensorv  and  motor  fibres.     The  anterior  division 


Chap.  XIX]  THE   NERVOUS   SYSTEM  383 

supplies  the  extremities  and  parts  of  the  body  in  front  of  the  spine. 
The  posterior  division  suppHes  the  muscles  and  skin  of  the  back  of 
the  head,  neck,  and  trunk.  Each  anterior  division  connects  with 
the  sympathetic  system  by  means  of  fibres  which  pass  from  the 
nerve  to  the  sympathetic  system  and  vice  versa.  Previous  to 
their  final  distribution  in  the  cervical,  sacral,  and  lumbar  re- 
gions these  nerves  form  plexuses  known  as  the  cervical,  sacral, 
and  lumbar  plexuses.  In  passing  to  the  viscera,  muscles,  skin, 
etc.,  these  terminal  nerves  follow  the  same  pathway  as  the  blood- 
vessels. 

Names  of  peripheral  nerves.  —  Many  of  the  larger  branches 
given  off  from  the  spinal  ner^'es  bear  the  same  name  as  the  artery 
which  they  accompany,  or  of  the  part  which  they  supply.  Thus 
the  radial  nerve  passes  down  the  radial  side  of  the  forearm,  in  com- 
pany with  the  radial  artery ;  the  intercostal  nerves  pass  between 
the  ribs  in  company  with  the  intercostal  arteries. 

Functions  of  the  spinal  cord  :  — 

(a)  Conduction,  -or  the  conveyance  of  impulses  and  sensations 
between  the  centres  and  the  periphery. 

(b)  Reflex  action,  i.e.  the  origination  of  an  impulse  or  action 
in  response  to  a  stimulation  from  the  periphery,  without  of 
necessity  involving  the  brain  in  the  act  or  even  without  con- 
sciousness of  the  reflex  act  on  the  part  of  the  individual. 

(c)  Automatic  acts,  i.e.  acts  set  up  primarily  in  the  cells  of 
the  cord  by  the  cells  themselves,  and  not  as  a  result  of  stimula- 
tion by  brain  cells  (voluntary  acts)  nor  as  result  of  peripheral 
stimulation. 

(d)  Inhibition  of  reflex  acts.  —  If  every  outside  stimulation 
were  allowed  its  full  effects  in  the  setting  up  of  reflex  acts,  the 
body  would  be  on  "  the  jump  "  all  the  time.  This  overactivity 
is  checked  unconsciously  by  the  cells  of  the  spinal  cord  endowed 
with  this  function. 

(e)  Transference,  i.e.  an  apparent  transferring  of  impulses 
from  one  set  of  fibres  to  another. 

BRAIN 

The  brain,  the  most  complex  and  largest  mass  of  nervous 
tissue  in  the  body,  is  contained  in  the  complete  bony  cavity 
formed  by  the  bones  of  the  cranium.     It  is  covered  by  three 


384  ANATOMY  FOR   NURSES  [Chap.  XIX 

membranes  (also  named  meninges),  —  the  dura  mater,  pia  mater, 
and  arachnoid. 

The  dura  mater  is  a  dense  membrane  of  fibrous  connective  tissue 
containing  a  great  many  blood-vessels.  It  is  arranged  in  two 
layers  and  the  layers  are  attached  except  in  a  few  places.  The 
external  layer  is  adherent  to  the  bones  of  the  skull,  and  forms  their 
internal  periosteum.  The  internal  layer  covers  the  brain  and 
sends  numerous  prolongations  inward  for  the  support  and  protec- 
tion of  the  different  lobes  of  the  brain.  These  projections  also 
form  sinuses  that  return  the  blood  from  the  brain,  and  sheaths 
for  the  nerves  that  pass  out  of  the  skull.  It  may  be  called  the 
protective  membrane. 

The  pia  mater  is  a  delicate  membrane  of  connective  tissue, 
containing  an  exceedingly  abundant  network  of  blood  and  lymph 
vessels.  It  dips  down  into  all  the  crevices  and  depressions  of  the 
brain,  carrying  the  blood-vessels  which  go  to  every  part.  It  may 
be  called  the  vascular  or  nutritive  membrane. 

The  arachnoid  is  a  delicate  serous  membrane  which  is  placed 
between  the  dura  mater  and  the  pia  mater.  With  the  exception 
of  the  longitudinal  fissure,^  it  passes  over  the  various  eminences  and 
depressions  on  the  surface  of  the  brain  and  does  not  dip  down  into 
them  like  the  pia  mater.  Between  the  arachnoid  and  the  pia 
mater  is  a  space  called  the  sub-arachnoid  space  in  w'hich  is  a  certain 
amount  of  fluid.  This  fluid  is  secreted  by  the  arachnoid  and  is 
called  the  cerebro-spinal  fluid.  It  serves  to  lubricate  the  other 
membranes  and  prevent  friction.  In  cases  of  meningitis,  i.e.  in- 
flammation of  these  membranes,  the  amount  of  this  fluid  is  very 
much  increased. 

Structure  of  the  brain.  —  The  whole  brain  appears  to  consist  of 
a  number  of  isolated  masses  of  gray  matter  —  some  large,  some 
small  —  connected  together  by  a  multitude  of  medullated  fibres 
(white  matter)  arranged  in  perplexing  intricacy.  But  a  general 
arrangement  may  be  recognized.  The  numerous  masses  of  gray 
matter  in  the  interior  of  the  brain  may  be  looked  upon  as  forming 
a  more  or  less  continuous  column,  and  as  forming  the  core  of  the 
central  nervous  system,  while  around  it  are  built  up  the  great 
mass  of  the  cerebrum  and  the  smaller  mass  of  the  cerebellum.  This 
central  core  is  connected  by  various  bundles  of  fibres  with  the 

iSee  page  389. 


Chap.  XIX]  THE  NERVOUS  SYSTEM  385 

spinal  cord,  besides  being,  as  it  were,  a  continuation  of  the  gray- 
matter  in  the  centre  of  the  cord.  It  is  also  connected  at  its 
upper  end  by  numberless  fibres  to  the  gray  matter  on  the  surface 
of  the  cerebrum. 

Weight  of  the  brain.  —  With  the  exception  of  the  whale  and  the 
elephant,  the  human  brain  is  heavier  than  that  of  any  of  the  lower 
animals.  The  average  weight  of  the  brain  in  the  male  is  forty-nine 
and  a  half  ounces  (1403  grams) ;  in  the  female,  forty-four 
ounces  (1247  grams).  It  appears  that  the  weight  of  the  brain 
increases  rapidly  up  to  the  seventh  year,  more  slowly  to  between 
sixteen  and  twenty,  and  still  more  slowly  to  between  thirty  and 
forty,  when  it  reaches  its  maximum  weight.  Beyond  this  age  the 
brain  diminishes  slowly  in  weight,  about  an  ounce  every  ten  years. 

Divisions  of  the  brain.  —  The  brain  is  divided  into  four  principal 
parts :  the  cerebrum,  the  cerebellum,  the  pons  Varolii,  and  the 
medulla  oblongata. 

The  medulla  oblongata. — The  medulla  oblongata,  also  known  as 
the  spinal  bulb,  is  continuous  with  the  spinal  cord,  which,  on  passing 
into  the  cranial  cavity  through  the  foramen  magnum,  widens  into 
an  oblong-shaped  mass.  It  is  directed  backward  and  downward, 
its  anterior  surface  resting  on  a  groove  in  the  occipital  bone,  and 
its  posterior  surface  forming  the  floor  of  a  cavity  between  the 
two  halves,  or  hemispheres,  of  the  cerebellum.  It  is  hollow  and  the 
cavity,  called  the  fourth  ventricle,  is  an  expanded  continuation 
of  the  tiny  central  canal  which  runs  throughout  the  whole  length 
of  the  spinal  cord.  The  gray  matter  is  found  in  the  interior,  and 
the  white  matter  on  the  exterior ;  most  of  the  gray  matter  is  found 
on  the  floor  of  the  fourth  ventricle,  and  from  this  gray  matter  arise 
most  of  the  cranial  nerves.  The  medulla  has  an  anterior  and  a 
posterior  median  fissure ;  at  the  lower  part  of  the  anterior  fissure 
are  nerve-fibres  which  cross  from  one  side  to  the  other  or  decussate. 

Functions  of  the  medulla  oblongata.  —  The  functions  of  the 
medulla  are  similar  to  the  first  three  listed  under  the  functions  of 
the  cord,  i.e.  conduction,  reflex  action,  and  automatic  action. 

As  all  the  impressions  passing  between  the  brain  and  spinal  cord 
must  be  transmitted  through  the  medulla,  the  function  of  con- 
duction is  a  very  important  one.  As  previously  stated,  the 
medulla  contains  important  vital  and  reflex  centres.  The  prin- 
cipal ones  are :  — 
2c 


386  ANATOMY  FOR  NURSES  [Chap.  XIX 

(1)  The  respiratory  centres  for  regulating  the  function  of  respi- 
ration. 

(2)  Accelerator  centres  for  the  heart. 

(3)  Vasomotor  centre  to  regulate  size  of  arterioles  in  any  part 
of  the  body,  thus  controlling  the  amount  of  blood  furnished  to 
that  part. 

(4)  Other  centres,  such  as  the  vomiting  centre,  heat  control- 
ling centre,  etc. 

The  student  will  readily  appreciate  that,  the  medulla  being  the 
seat  of  such  important  centres  as  those  controlling  respiration 
and  the  heart's  action,  if  the  medulla  be  seriously  injured,  death 
will  result. 

Cerebellum.  —  The  cerebellum,  or  "  little  brain,"  occupies  the 
lower  and  back  of  the  skull  cavity,  overhanging  the  medulla 
oblongata.  It  is  of  a  flattened,  oblong  shape,  and  measures 
from  three  and  a  half  inches  to  four  inches  (87  to  100  mm.)  trans- 
versely, and  from  two  to  two  and  a  half  inches  (50  to  03  mm.) 
from  before  backward.  It  is  divided  in  the  middle  line  into  two 
lateral  lobes,  or  hemispheres,  and  a  median  lobe,  by  a  central 
depression,  each  lobe  being  subdivided  by  fissures  into  smaller 
portions.  The  surface  of  the  cerebellum  consists  of  gray  matter 
and  is  traversed  by  numerous  curves,  or  furrows,  which  vary  in 
depth.     The  interior  consists  of  white  matter. 

Peduncles  of  cerehcUiim. — The  cerebellum  is  connected  with 
the  rest  of  the  cerebro-spinal  system  by  many  white  nerve- 
fibres  grouped  in  bundles  called  the  peduncles. 

The  peduncles  are  arranged  in  three  pairs.  The  anterior 
(superior)  peduncles  pass  forward  from  the  cerebellum  to  enter 
into  the  cerebrum.  The  posterior  (inferior)  peduncles  pass  down 
to  the  medulla,  where  they  are  known  as  the  restiform  bodies. 
The  middle  pair  pass  into  and  make  up  the  larger  portion  of 
the  pons  Varolii,  thus  serving  as  a  means  of  intercommunication 
between  the  two  halves  of  the  cerebellum.  Thus  it  is  seen  that 
the  cerebellum  communicates  most  freely  with  the  entire  cerebro- 
spinal system. 

Functions  of  the  cerebellum.  —  The  principal  function  of  the 
cerebellum  seems  to  be  the  coordination  of  ordinary  movements, 
and  the  maintenance  of  equilibrium.  The  reason  for  this  belief 
is  that  disease  or  destruction  of  the  cerebellum  apparently  exerts 


Chap.  XIX] 


THE  NERVOUS   SYSTEM 


387 


no  malign  influence  on  sensory  nerves  nor  upon  the  intellect. 
The  motor  system  is,  however,  profoundly  deranged.  IVIotion 
is  itself  not  destroyed,  but  coordination  is  so  interfered  with  that 
movements  of  one  part  of  the  body  cannot  be  adapted  to  other 
parts. 

Pigeons  deprived  of  the  cerebellum  will  fly  if  thrown  from  a  roof 


XT' 
XII- 


SYLVIAM 

FISSURC 

lion    PER- 
ED   SPACE 

INFUNOI* 
BULUM 

POSTEPIOR  PER- 
FORATED SPACE 
CRUS   CEREBRI 


( 

'i    mSm  I'm     iiiii— imAWiT^ 


wi..i    JZ_J_  T1...!II1!1L^\«— ( 


CEREBELLUM 


Fig.  183.  —  Under  Surface  of  the  Brain,  showing  the  Superficial 
Origins  of  the  Cranial  Nerves.  The  Roman  numerals  indicate  the  nerves. 
(Gerrish.) 

but  the  delicacy  of  the  coordination  being  lost,  they  turn  a  series 
of  somersaults  in  the  air  and  soon  fall  to  the  ground. 

Pons  Varolii.  - —  The  pons  Varolii,  or  bridge  of  Varolius,  lies  in 
front  of  the  upper  part  of  the  medulla  oblongata.  It  consists 
of  interlaced  transverse  and  longitudinal  white  nerve-fibres 
intermixed  with  gray  matter.  The  transverse  fibres  are  those 
derived  from  the  middle  peduncles  of  the  cerebellum  and,  as 
already  stated,  serve  to  join  its  two  halves.  The  longitudinal 
fibres  join  the  medulla  with  the  cerebrum. 

Functions  of  pons  Varolii.  —  The  pons  is  a  bridge  of  union  be- 
tween the  two  halves  of  the  cerebellum  and  a  bridge  between 


388 


ANATOMY   FOR   NURSES 


[Chap.  XIX 


the  medulla  and  the  cerebrum.     It  is  also  a  port  of  exit  for  the 
fifth,  sixth,  seventh,  and  eit^hth  cranial  nerves. 

Cerebrum.  —  The  cerebrum  is  by  far  the  largest  part  of  the 
brain.  It  is  egfj-shaped,  or  ovoidal,  and  fills  the  whole  of  the 
upper  portion  of  the  skull.  The  entire  surface,  both  upper  and 
under,  is  composed  of  layers  of  gray  matter,  and  is  called  the  cortex 
because,  like  the  bark  of  a  tree,  it  is  on  the  outside.  The  bulk  of  the 
white  matter  in  the  interior  of  the  cerebrum  consists  of  very  small 
fibres  running  in  three  principal  directions :    (1)  from  above  down- 


JNTCRNAL  JUCUUIfl 

P'iG.  184.  —  Falx  Cerebri  and  Tentorium,  Left  Lateral  View.     (Gerrish.) 

ward,  (2)  from  the  front  backward,  and  {'.])  from  side  to  side. 
The  fibres  link  the  dift'erent  parts  of  the  brain  together,  and  con- 
nect the  brain  with  the  spinal  cord. 

Fissures  and  convolutions.  —  In  early  life  the  cortex  of  the 
cerebrum  is  comparatively  smooth,  but  as  time  passes  and  the 
brain  develops,  the  surface  becomes  covered  with  depressions 
which  vary  in  depth.  The  deeper  depressions  are  called  fissures, 
the  more  shallow  ones  sulci,  and  the  ridges  between  the  sulci  are 
called  convolutions.  The  fissures  and  sulci  are  infoldings  of 
gray  matter,  consequently  the  more  numerous  and  deeper  they 
are,  the  greater  is  the  amount  of  gray  matter,  and  the  greater 
is  the  extent  of  surface  for  che  termination  of  fibres.  The 
number  and  depth  of  these  fissures  and  sulci  is  thought  to  bear  a 


Chap.  XIX] 


THE  NERVOUS   SYSTEM 


389 


close  relation  to  intellectual  power ;  babies  and  idiots  have  few 
and  shallow  folds,  while  the  brains  of  men  of  intellect  are  always 
markedly  convoluted.  There  are  five  important  fissures  which  are 
always  present.     They  are  the  following  :  — 

(1)  The  Great  Longitudinal  Fissure,  which  extends  from  the 
back  to  the  front  of  the  cerebrum,  and  almost  completely  divides 
it  into  two  hemispheres,  the  two  halves,  however,  being  connected 
in  the  centre  by  a  broad,  transverse  band  of  white  fibres  called  the 
corpus  callosum.  A  process  of  the  dura  mater  extends  down  into 
this  fissure  and  separates  the  two  cerebral  hemispheres.  It  is  called 
the  falx  cerebri,  because  it  is  narrow  in  front,  and  broader  behind, 


Fig.  185.  —  External  View  of  Outer  Side  of  Right  Cerebral  Hemi- 
sphere, SHOWING  Rolando,  Sylvian,  and  Parieto-occipital  Fissures  to- 
gether with  Principal  Convolutions.     (Collins.) 


thus  resembling  a  sickle  in  shape.  In  a  previous  chapter  it  was 
stated  that  the  blood  was  returned  from  the  brain  in  venous  chan- 
nels called  sinuses.  Two  important  sinuses  are  lodged  between 
the  layers  of  the  falx  cerebri.  The  superior  longitudinal  sinus  is 
contained  in  the  upper  border,  and  the  inferior  longitudinal  sinus 
in  the  lower  border. 

(2)  The  Transverse  Fissure,  which  is  between  the  cerebrum  and 
the  cerebellum.  A  process  of  the  dura  also  extends  into  this  fis- 
sure, and  covers  the  upper  surface  of  the  cerebellum  and  the 
under  surface  of  the  cerebrum.     It  is  called  the  tentorium  cerehelli. 


390 


ANATOMY  FOR   NURSES  [Chap.  XIX 


There  is  one  of  each  in  each 
hemisphere.  For  location  see 
Figs.  185  and  186. 


(3)  Fissure  of   Rolando,  or^ 

central  fissure. 

(4)  Fissure  of  Sylvius. 

(5)  Parieto-occipital  fissure.  ^ 
Lobes  of  the  cerebrum.  —  The  longitudinal  fissure  divides  the 

cerebrum  into  two  hemispheres,  and  the  transverse  fissure  divides 
the  cerebrum  from  the  cerebellum.  The  three  remaining  fissures 
divide  each  hemisphere  into  five  lobes.     With  one  exception  these 


Fig.  186.  —  Mesial   View   of   Left   Cerebral   Hemisphere,    showing  Ro- 

LANDIC      AND      PaRIETO-OCCIPITAL      FiSSURES,      TOGETHER      WITH      THE      PRINCIPAL 

Convolutions.     (Collins.) 


lobes  were  named  from  the  bones  of  the  cranium  under  which  they 
lie  ;   hence  they  are  known  as  :  — 

(1)  Frontal  lobe. 

(2)  Parietal  lobe. 

(3)  Temporal  lobe. 

(4)  Occipital  lobe. 

(5)  Central  lobe,  or  Island  of  Reil  (the  exception). 

(1)  The  frontal  lobe  is  that  portion  of  the  cerebrum  lying 
in  front  of  the  fissure  of  Rolando,  and  usually  consists  of  four  main 
convolutions. 

(2)  Parietal  lobe  is  bounded  in  front  by  the  fissure  of  Rolando, 
and  behind  by  the  parieto-occipital  fissure. 

(3)  Temporal  lobe  lies  below  the  fissure  of  Sylvius  and  in  front 
of  the  occipital  lobe. 


Chap.  XIX] 


THE  NERVOUS  SYSTEM 


391 


(4)  Occipital  lobe  occupies  the  posterior  extremity  of  the 
cerebral  hemisphere.  When  one  examines  the  external  surface  of 
the  hemisphere,  there  is  no  marked  separation  of  the  occipital  lobe 
from  the  parietal  and  temporal  lobes  that  lie  to  the  front ;  but 
when  the  surface  of  the  longitudinal  cleft  is  examined,  the  parieto- 
occipital fissure  serves  as  a  boundary  anteriorly  for  the  occipital 
lobe. 

(5)  Central  lobe,  or  Island  of  Reil,  is  not  seen  when  the  sur- 
face of  the  hemisphere  is  examined,  for  it  lies  within  the  fissure 


Fig.  187.  —  The  Lobes  of  the  Convex  Surface  of  the  Hemisphere,  Left 

Side.     (Gerrish.) 


of  Sylvius,  and  the  overlying  convolutions  of  the  parietal  and 
frontal  lobes  must  be  lifted  up  before  the  central  lobe  comes  into 
view. 

Ventricles  of  the  brain.  —  In  describing  the  spinal  cord,  ref- 
erence was  made  to  the  central  canal,  being  a  minute  canal  running 
through  the  centre  of  the  cord  throughout  its  entire  length,  thus 
converting  the  cord  into  a  tube  with  exceedingly  thick  walls  but 
very  small  internal  calibre.  In  the  brain  proper  this  same  central 
channel  persists,  and  just  as  the  walls  or  solid  portions  of  the  brain 
are  directly  continuous  with  the  wall  or  solid  portion  of  the  spinal 
cord,  so  is  the  internal  hollow  of  the  brain  directly  continuous 
with  the  hollow  or  central  canal  of  the  cord.  The  cavity  in  the 
brain  presents  some  marked  differences  to  that  of  the  cord ;  while 


392  ANATOMY  FOR  NURSES       [Ch.^p.  XIX 

the  latter  is  a  straight,  fairly  uniform  canal  of  very  small  diameter, 
the  former  is  at  some  points  very  narrow,  and  at  others  much 
widened  out  so  as  to  form  quite  jrood-sized  chambers,  and  these 
chambers  are  called  the  ventricles  of  the  brain.  These  ventricles 
are  filled  with  cerebro-spinal  fluid,  just  as  the  canal  of  the  cord  is 
like\vise  filled  with  the  same  material. 

The  ventricles  are  five  in  number.  The  most  posterior  is  the 
enlargement  or  expansion  of  the  central  canal,  occupying  the  sub- 
stance of  the  medulla  oblongata,  and  is  called  the  "  fourth  ven- 
tricle." Leading  forward  from  the  anterior  end  of  the  fourth 
ventricle,  the  calibre  of  the  canal  again  narrows  to  a  very  small 
diameter ;  the  tube,  on  reaching  the  brain  substance  uniting  the 
two  halves  of  the  cerebrum,  again  expands  into  a  somewhat  smaller 
chamber,  called  the  "third  ventricle."  The  small  canal  already 
mentioned  as  joining  the  third  and  fourth  ventricles  is  known  as 
the  aqueduct  of  Sylvius. 

Toward  the  forward  end  of  the  third  ventricle  there  are  noted 
two  small  channels,  the  foramina  of  Monro,  one  on  either  side 
leading  in  a  direction  forward,  upward,  and  outward,  each  fora- 
men leading  into  a  very  large  ventricle  occupying  the  centre 
of  its  corresponding  cerebral  hemisphere,  called  the  lateral 
ventricles. 

The  fifth  ventricle  is  very  small,  lies  between  the  two  lateral 
ventricles,  and  is  not  in  communication  with  the  other  ventricles. 

The  student  will  thus  see  that  both  the  brain  and  spinal  cord 
are  really  hollow.  In  some  portions,  however  (as  the  spinal 
cord),  the  interior  cavity  is  so  minute  and  the  walls  so  exceed- 
ingly thick  that  the  cavity  is  a  negligible  quantity,  and  the 
mass  can  practically  be  considered  as  solid ;  on  the  other  hand, 
in  the  case  of  the  ventricles,  especially  the  lateral  ventricles,  the 
cavity  is  large  enough  to  occupy  an  appreciable  space,  and  may 
become  overdistended  with  cerebro-spinal  fluid  in  certain  con- 
ditions of  disease. 

On  the  whole,  the  cavity  of  the  brain  and  cord  occupies  a  more 
or  less  central  position,  having  its  walls  at  any  given  point  of 
about  equal  thickness ;  at  certain  points,  however  (the  third 
and  fourth  ventricles  especially),  the  cavity  approaches  so  close 
to  the  surface  that  at  these  points  one  of  its  walls  is  thinned  out 
to  only  a  microscopic  thickness. 


Chap.  XIX] 


THE  NERVOUS  SYSTEM 


393 


Function  of  the  cerebrum.  —  The  nerve-centres  which  govern 
all  our  mental  activities  and  the  coordination  of  movements  are 
centred  in  the  cerebrum.  These  centres  are  the  seat  of  reason, 
intelligence,  will,  memory,  and  all  the  higher  emotions  and 
feelings. 

Localization  of  brain  function.  —  As  the  result  of  numerous 
experiments  on  animals,  and  close  observation  of  individuals 
suffering  from  cerebral  diseases  or  wounds,  physiologists  have  been 
able  to  localize  certain  areas  in  the  brain  which  control  motor  and 
sensory  activity.     They  have  also  been  able  to  gain  some  knowl- 


FiG.  188.  —  Localization  of  Function  in  the  Cerebral  Cortex. 
■  "  Surgical  Anatomy.") 


(Woolsey's 


edge  of  the  areas  in  the  cerebrum  which  are  concerned  with  the 
higher  mental  activities. 

Names  of  areas.  —  That  portion  of  the  cerebrum  which  governs 
muscular  movement  is  known  as  the  motor  area,  the  portions 
controlling  sensation  as  the  sensory  areas,  and  those  connected 
with  the  higher  faculties,  such  as  reason  and  will,  as  association 
areas. 

Motor  areas.  —  The  surface  of  the  brain  assigned  to  the  func- 
tion of  motion  is  the  posterior  part  of  the  frontal  lobe,  i.e.  the 
gray  matter  immediately  in  front  of  the  fissure  of  Rolando. 

A  knowledge  of  the  motor  area  enables  physicians  and  surgeons, 
in  many  cases  of  convulsions  or  paralysis,  to  locate  the  exact  por- 
tion of  the  brain  that  is  affected,  by  close  observation  of  the  part 


394  ANATOMY  FOR  NURSES  [Chap.  XIX 

of  the  body  involved  in  the  convulsion  or  loss  of  function.  In  this 
connection  it  must  be  remembered  that  the  fibres  extending  from 
the  brain  into  the  cord,  and  from  the  cord  into  the  brain,  decussate 
or  cross  in  the  medulla. 

Sense  areas.  —  The  term  "  sense  areas  "  is  used  to  designate  those 
parts  of  the  brain  to  which  sensation  is  due,  and  which  control 
vision,  hearing,  smell,  and  taste.  The  visual  area  is  situated  in 
part  of  the  occipital  lobe ;  the  auditory  area  in  the  superior  part 
of  the  temporal  lobe ;  and  the  olfactory  and  gustatory  areas  are 
in  the  anterior  part  of  the  temporal  lobe. 

Location  of  speech  areas.  —  "  The  speech  areas,  four  in  number 
and  in  kind,  are  in  the  left  hemisphere  in  right-handed  persons  and 
in  tlie right  in  left-handed  persons.  There  are  two  types  of  aphasia, 
which  is  the  loss  of  the  power  of  speech,  known  as  motor  and  sen- 
sory aphasia.  The  motor  speech  centre  lies  in  the  posterior  part 
of  the  third  frontal  convolution  just  in  front  of  the  centre  of  the 
muscles  of  speech.  A  lesion  of  the  motor  speech  centre  causes 
motor  aphasia,  in  which  there  is  a  loss  of  the  word-forming  power, 
although  the  tongue  is  movable  and  the  patient  may  understand 
spoken  and  written  language  and  knows  what  he  wants  to  say. 
It  is  as  if  memory  of  the  motor  combinations  essential  to  produce 
speech  were  lost. 

The  power  of  writing  is  usually  lost  with  motor  speech.  The 
probable  location  of  its  cortical  centre  is  in  the  posterior  two-thirds 
of  the  first,  and  perhaps  in  the  second,  temporal  convolution.  A 
lesion  here  causes  '  word  deafness,'  a  sensory  aphasia  in  which  the 
memory  of  the  sounds  of  words  is  lost  so  that  they  are  not  under- 
stood, though  hearing  may  be  normal. 


Word-blindness  (alexia),  or  the  loss  of  memory  of  printed  or 
written  language,  is  caused  by  a  lesion  in  the  occipital  lobe, 
though  sight  itself  may  be  normal. 

"Thus  the  basis  of  language  is  a  series  of  memory  pictures: 
(1)  of  the  sound  of  words;  (2)  of  their  appearance;  (3)  of  the 
effort  necessary  to  enunciate  them  ;  and  (4)  to  write  their  sjTnbols. 
As  these  memory  pictures  are  connected  with  each  other  and  with 
others  that  make  up  the  concept  by  subcortical  association  fibres 
passing  between  them,  a  lesion  in  any  of  these  association  tracts 


Chap.  XIX]  THE   NERVOUS   SYSTEM  395 

also  leads  to  a  defect  of  speech."     (Woolsey,  "  Applied  Surgical 
Anatomy.") 

Association  areas.  —  Those  parts  of  the  cerebral  cortex  which  are 
not  the  location  of  special  centres  are  called  association  areas. 
It  is  here  that  the  information  received  by  the  various  sense  centres 
is  built  up  and  coordinated  into  concepts  or  perceptions.  The 
various  parts  of  the  association  areas  are  connected  with  the 
sense  centres  by  means  of  association  fibres.  The  localization  of 
function  in  the  association  areas  is  not  yet  determined. 

THE  CRANIAL  NERVES 

The  cranial  nerves  consist  of  twelve  pairs.  They  each  have  a 
superficial  and  a  deep  origin.  The  superficial  origin  is  the  point 
where  they  emerge  from  the  under  surface  of  the  cerebrum  and  the 
medulla,  but  they  can  be  traced  back  to  various  centres  in  the 
higher  part  of  the  brain,  and  these  centres  constitute  their  deep 
origin. 

Classification.  —  The  cranial  nerves  are  of  three  varieties : 
(1)  sensory  nerves,  (2)  motor  nerves,  and  (3)  mixed  nerves  or 
those  containing  both  sensory  and  motor  fibres.  Many  of  the 
cranial  nerves  arise  from  several  nerve-centres,  and  therefore  con- 
sist of  several  bundles  of  nerve-fibres.  After  these  nerves  leave 
the  cranium  they  split  up  into  branches  that  are  widely  distrib- 
uted. 

Numbers  and  names.  —  They  are  named  numerically  according 
to  the  order  in  which  they  arise  from  the  brain.  Other  names 
are  also  given  to  them,  derived  from  the  parts  to  which  they  are 
distributed  or  from  their  functions.  Taken  in  their  order  from 
before  backward,  they  are  as  follows  :  — 

1.  Olfactory  (sensory). 

2.  Optic  (sensory). 

3.  Motor  oculi  (motor). 

4.  Pathetic,  or  trochlear  (motor). 

5.  Trifacial,  or  trigeminal  (mixed,  but  mainly  sensory). 

6.  Abducens  (motor). 

7.  Facial  (motor). 

8.  Auditory  (sensory). 

9.  Glossopharyngeal  (mixed). 

10.  Pneumogastric,  or  vagus  (mixed). 


396  ANATOMY   FOR   NURSES  [Chap.  XIX 

11.  Spinal  accessory  (motor). 

12.  Hypoglossal  (motor). 

The  following  doggerel  which  has  been  handed  down  through 
countless  generations  of  students  may  assist  the  beginner  in  learn- 
ing the  order  of  the  cranial  nerves.  Each  capital  letter  denotes  a 
cranial  nerve.  On  Old  ^Manhattan's  Peaked  Tops  A  Finn  And 
German  Picked  Some  Hops. 

(1)  The  olfactory  ner\'e  is  the  special  nerve  of  the  sense  of  smell 
Its  origin  is  in  the  olfactory  bulb,  and  its  peripheral  fibres  are 
distributed  to  the  upper  third  of  the  nasal  cavity. 

(2)  The  optic  nerve  is  the  special  nerve  of  the  sense  of  sight.  Its 
cell-bodies  are  situated  in  the  retinal  coat  of  the  eye. 

(3)  The  motor  oculi  nerve  supplies  all  the  muscles  of  the  eye 
except  the  superior  oblique  and  the  external  rectus.  It  originates 
in  the  gray  matter  of  the  pons  Varolii. 

(4)  The  pathetic,  or  trochlear,  nerve  supplies  only  the  superior 
oblique  muscle  of  the  eye.     It  arises  close  to  the  preceding  nerve. 

(5)  The  trifacial  has  two  roots,  —  a  dorsal,  or  sensory,  and  a 
ventral,  or  motor.  The  fibres  from  the  two  roots  coalesce  into  one 
trunk,  and  then  subdivide  into  three  large  branches  :  (1)  the  oph- 
thalmic, (2)  the  superior  maxillary,  and  (3)  the  inferior  maxillary. 
The  ophthalmic  branch  is  the  smallest,  and  is  a  sensory  nerve.  It 
supplies  the  eyeball,  the  lacrimal  gland,  the  mucous  lining  of  the  eye 
and  nose,  and  the  skin  and  muscles  of  the  eyebrow,  forehead,  and 
nose.  The  superior  maxillary,  the  second  division  of  the  fifth,  is 
also  a  sensory  nerve,  and  supplies  the  skin  of  the  temple  and  cheek, 
the  upper  teeth,  and  the  mucous  lining  of  the  mouth  and  pharynx. 
The  inferior  maxillary  is  the  largest  of  the  three  divisions  of  the 
fifth,  and  is  both  a  sensory  and  a  motor  nerve.  It  sends  branches 
to  the  temple  and  the  external  ear ;  to  the  teeth  and  lower  jaw ; 
to  the  muscles  of  mastication ;  it  also  supplies  the  tongue  with  a 
special  nerve  (the  lingual)  of  the  sense  of  taste.  The  cell-bodies 
of  the  motor  fibres  are  situated  in  the  pons ;  while  those  of  the 
sensory  fibres,  as  in  the  case  of  the  spinal  nerves,  are  situated  in  a 
ganglion.     This  ganglion  is  called  the  Gasserian  ganglion. 

(6)  The  abducens  nerve  supplies  the  external  rectus  muscle  of 
the  eye. 

(7)  The  facial  nerve  is  the  motor  nerve  of  all  the  muscles 
of  expression  in  the  face ;  it  also  supplies  the  neck  and  ear.     Its 


Chap.  XIX]  THE   NERVOUS   SYSTEM  397 

cells  of  origin,  like  those  of  the  abducens  nerve,  are  situated  in  the 
medulla. 

(8)  The  auditory  nerve  is  the  special  nerve  of  the  sense  of  hear- 
ing. It  arises  from  cells  which  compose  the  organ  of  Corti  in  the 
internal  ear,  to  which  its  fibres  are  exclusively  distributed. 

(9)  The  glossopharyngeal  nerve  is  distributed,  as  its  name 
indicates,  to  the  tongue  and  pharynx,  being  the  nerve  of  sensa- 
tion to  the  mucous  membrane  of  the  pharynx,  of  motion  to  the 
pharyngeal  muscles,  and  the  special  nerve  of  taste  to  part  of  the 
tongue. 

(10)  The  pneumogastric  nerve  has  a  more  extensive  distribu- 
tion than  any  of  the  other  cranial  nerves,  passing  through  the  neck 
and  thorax  to  the  upper  part  of  the  abdomen.  It  contains  both 
motor  and  sensory  fibres.  It  supplies  the  organs  of  voice  and 
respiration  with  motor  and  sensory  filaments ;  and  the  pharynx, 
oesophagus,  stomach,  and  heart  with  motor  fibres  (cardiac  inhibi- 
tory). 

(11)  The  spinal-accessory  nerve  consists  of  two  parts  :  one,  the 
spinal  portion,  and  the  other,  the  accessory  portion  to  the  tenth 
nerve.  It  is  a  motor  nerve  supplying  certain  muscles  of  the  neck. 
It  differs  from  the  other  cranial  nerves  in  arising  from  the  spinal 
cord,  but  it  leaves  the  skull  by  the  same  aperture  as  the  pneumo- 
gastric and  glossopharyngeal. 

(12)  The  hypoglossal  nerve  is  the  motor  nerve  of  the  tongue. 
Reflex  acts.  —  The    student   doubtless    can  understand    from 

the  preceding  portions  of  this  chapter  the  general  arrange- 
ment of  the  nervous  tissues,  and  how  simple  impulses  arising 
in  brain  cells  pass  along  nerve-fibres,  and,  terminating  in  the 
end  organs,  produce,  for  example,  a  muscular  contraction  (mo- 
tor impulse),  or  how  an  outside  stimulus  applied  to  the  skin 
will  set  up  vibrations  in  suitable  end  organs  to  be  transmitted 
along  sensory  nerve-fibres  to  end  in  sensory  brain  cells  and  pro- 
duce the  appreciation  by  the  mind  of  the  fact  that  the  stimu- 
lus has  been  applied.  All  of  these  are  simple,  straightforward 
functions  of  the  neurones.  There  is  a  host  of  other  more  com- 
plex acts  in  which,  for  example,  two  or  more  neurones  take  part, 
which  carry  out  a  train  of  functions,  each  depending  on  the  other, 
and  may  carry  out  their  destiny  so  smoothly  and  accurately,  so 
that  the   perception   of  the  mind  or  consciousness  of  the   act 


398 


ANATOMY  FOR   NURSES 


[Chap.  XIX 


be  entirely  wanting,  thus  saving  the  brain  an  enormous  amount 
of  wear  and  tear. 

The  simplest  of  these  nervous  mechanisms  is  the  reflex  arc, 
and  the  simplest  form  of  nervous  activity  is  "  reflex  action." 
Tw^o  neurones  enter  into  the  formation  of  a  reflex  arc,  a  sensory 
neurone  and  a  motor  neurone.  On  applying  an  appropriate 
stimulus  to  the  peripheral  end  of  the  sensory  neurone,  an  impulse 
is  generated  which  passes  along  the  sensory  neurone  to  the  nerve- 


Fro.  189.  —  Reflex  Arc.    S,  sensory  neuron  arising  in  tactile  corpuscles.    M,  mo- 
tor neuron  ending  in  muscle  fibres.     R,  interlacing  of  dendrites.      (Collins.) 


centre,  and  back  again  to  the  periphery  by  the  motor  neurone ; 
and,  since  the  motor  neurone  terminates  in  a  muscle  (or  some 
similar  mechani.sm),  we  get  a  muscular  response  as  the  indirect 
result  of  stimulating  the  sensory  nerve. 

This  is  a  reflex  act,  and  usually  the  exchange  between  the  sensory 
and  motor  impulse  takes  place  in  the  spinal  cord.  The  sensory 
impulse,  after  delivering  its  stimulus  to  the  motor  neurone,  may 
continue  on  up  the  spinal  cord  to  terminate  in  the  brain  and 
give  to  the  individual  the  consciousness  of  the  stimulus,  or,  on 
the  other  hand,  the  sensory  impulse,  after  arousing  the  motor 
act,  may  cease,  and  no  impulse  be  transmitted  to  the  brain, 


Chap.  XIX]  THE   NERVOUS   SYSTEM  399 

the  individual  thus  being  totally  oblivious  to  the  reflex  act. 
Even  if  the  sensory  impulse  goes  to  the  brain,  the  consciousness 
of  the  sensation  by  the  individual  is  always  later  in  point  of  time 
than  the  reflex  act.  For  example :  If,  without  a  person's 
knowledge  that  the  experiment  is  to  be  tried,  one's  finger  be 
pricked  with  a  pin,  the  finger  is  instantly  pulled  back  and  the 
act  is  done  before  the  individual  is  conscious  of  the  pain.  In 
this  experiment  the  sensory  impulse  of  the  pin  prick  passed  to 
the  spinal  cord,  set  up  the  motor  action  necessary  to  withdraw 
the  finger,  and  then  passed  on  to  the  brain.  Again,  many 
sensory  impulses  produce  their  reflex  without  the  brain  bother- 
ing about  the  matter  at  all.  An  example  of  this  is  the  act  of 
walking.  Walking  is  an  exceedingly  difficult  accomplishment 
to  learn,  acquired  in  childhood  only  after  laborious  eft'ort,  not 
because  the  muscles  are  weak,  but  because  the  human  individual, 
when  erect,  is  in  an  exceedingly  unstable  state  of  equilibrium, 
and  constant  contraction  and  relaxation  of  groups  of  muscles 
is  necessary  to  maintain  the  balance.  Here  the  sensory  impulses 
of  being  out  of  balance  arouse  motor  impulses  in  first  one  set  of 
muscles,  then  another,  to  restore  the  balance.  At  first  this  is  only 
accomplished  with  mental  appreciation  of  the  performance ;  later 
on  one  learns  the  trick,  and  the  act  of  walking  or  standing  upright 
is  performed  without  a  moment's  thought  or  even  consciousness 
of  the  difficult  task  we  are  doing  purely  by  reflex  activity. 

The  kind  of  stimulus  which  will  call  forth  the  nerve-impulse 
depends  on  the  peripheral  termination  of  the  afferent  nerve,  and 
the  kind  of  response  which  an  appropriate  stimulus  will  call 
forth  depends  on  the  mode  of  termination  of  the  efferent  nerve. 
Thus,  light  falling  on  the  retinal  coat  of  the  eye  (the  peripheral 
termination  of  the  sensory  nerve)  generates  an  impulse  which 
passes  to  the  centre  by  the  optic  nerve,  and  returns  again  by  the 
motor  oculi  nerve  to  the  periphery ;  viz.  the  sphincter  of  the  iris 
(the  termination  of  the  motor  nerve),  which  by  its  contraction 
narrows  the  pupil.  Hence  arises  the  well-known  phenomenon  of 
the  contraction  of  the  pupil  when  light  falls  upon  the  eye. 

Also  stimulation  of  taste  fibres  in  the  mouth  causes  a  reflex 
secretion  of  the  salivary  glands.  Innumerable  examples  of  this 
kind  might  be  given.  Indeed,  since  physical  life  has  been  well- 
defined   as   the    continual   response   to    external    stimuli,    reflex 


400 


ANATOMY  FOR   NURSES 


[Chap.  XIX 


action,  which  is  the  chief  inethod  of  response,  is  the  most  im- 
portant vital  phenomenon  peculiar  to  animals  possessing  any 
nervous  svstem  whatsoever. 


Fig.  190.  —  Diagram  of  Nervous  System,  a,  a,  cortex  of  cerebral  hemi- 
spheres ;  h,  b,  cell-body  and  dendrites  of  upper  motor  neurone,  situated  in  cerebral 
cortex  ;  h',  axis  cylinder  of  ujjper  motor  neuroiic,  branching  at  its  termination  near 
the  dendrites  of  lower  motor  neurone,  situated  in  the  ventral  horn  of  gray  matter 
in  the  spinal  cord  ;  B,  axis  cylinder  of  lower  motor  neurone  passing  to  its  termina- 
tion in  a  voluntary  muscle  fibre  B"  ;  C,  cell-body  and  dendrites  of  upper  sensory 
neurone,  situated  in  the  medulla  oblongata  ;  C,  C,  axis  cylinders  of  upper  sensory 
neurone,  terminating  in  cortex  ;  c,  cell-body  of  lower  sensory  neurone,  situated  in 
the  dorsal  root  ganglion  ;  c'",  dendrite  of  lower  motor  neurone,  conducting  impulses 
from  the  periphery  to  the  central  nervous  system  ;  c",  long  branch  of  lower  sen- 
sory neurone,  conducting  impulses  toward  the  brain ;  c',  short  branch  of  lower 
sensory  neurone,  conducting  impulses  direct  to  ventral  horn.  (For  the  sake  of 
simplicity  the  connections  with  the  cerebellum  are  omitted.) 


Chap.  XIX] 


SUMMARY 


401 


A  careful  study  of  Figs.  189  and  190  will  make  the  typical 
reflex  path  perfectly  intelligible  to  the  student,  and  should  on  no 
account  be  omitted. 

All  nervous  action  is  fundamentally  similar  to  this  typical 
reflex  action.  Usually  the  number  of  neurones  involved  is  greater, 
often  very  much  greater,  than  two.  The  fewer  the  neurones, 
the  simpler  and  more  obviously  machine-like  the  reaction.  The 
more  complex  the  path,  the  more  uncertain  and  variable  the 
reaction.  When  the  path  of  the  impulse  does  not  involve  the 
cerebrum,  the  reactions  are  unconscious  and  comparatively  sim- 
ple ;  but  if  the  cerebral  cortex  be  involved,  the  passage  of  the 
nerve-impulse  is  accompanied  by  the  phenomenon  of  conscious- 
ness, and  the  reaction  may  be  exceedingly  complex,  uncertain, 
and  long  delayed.  These  are  the  characteristics  of  what  we  call 
voluntary  reactions.  But,  although  the  phrase  "  reflex  action  " 
is  usually  confined  to  those  actions  which  are  involuntary  and 
of  which  we  are  unconscious,  yet  all  nervous  action  is  essentially 
the  same,  differing  only  in  the  complexity  of  the  path  followed 
by  the  impulse. 


Nervous 
System 


Parts  of 
Nervous 
System 


Func- 
tions 


Divisions  < 


SUMMARY 

Brain. 
Spinal  cord. 
Sympathetic  ganglia. 
Nerve-trunks. 
Organules. 
■  Makes  possible  mental  activities. 
Recognition  of  surroundings  and  accommodation 

to  same. 
Motion  and  sensation. 
Equilibrium  and  coordination. 
Brain. 
Spinal  cord. 

C  Cerebro-spinal. 
Nerves  <  Cranial  nerves. 
I  Spinal  nerves. 

1.  Vertebral  ganglia. 

2.  Collateral  ganglia. 

3.  Terminal  ganglia  and  plexuses. 

4.  Sympathetic     ganglia     in     the 
brain  and  cord. 


Central  ner- 
vous   sys-  < 
tem 


SjTnpathctic 
system 


2d 


402 


ANATOMY   FOR   NURSES 


[Chap.  XIX 


Property 
of  nerve- 
tissue 


I  Irritability  or  the  power  to  respond  to  stimulation. 
Conductivity  or  the  power  to  transmit  stimuli. 


Neurone 
or  Nerve-  ■ 
ceU 


Cell- 
body 


Cell- 
processes 


Cell-body 


Dendrites. 

Axis  cylinder  process. 

Nerve-fibres. 

Collaterals. 

Nerve-endings. 

(  Unipolar. 
Varieties  i  Bipolar. 

i  Multipolar. 

Nutrition. 

Gives  rise  to  nervous  impulses. 

- ,    vc      •         1       f  Inhibition. 
Modifies  impulses  i  „ 

[  Summation. 


Function  ■ 


Dendrites 


■  Short,  break  up  into  many  branches. 
Rough  outline  —  diminish  in  calibre. 
May  be  one,  or  many. 

.  Function  —  Collect  and  carry  impulses  to  cell-body. 
Synapse  —  Arborization    of    contiguous    processes,    not    an   anatomical 
continuation. 


Axis 

Cylinder 

Process 


Nerve- 
fibre 


Long,  smooth  outline,  diminishes  very  little. 
Gives  off  collaterals. 
Continued  as  core  of  nerve-fibre. 
Function  —  Carry  impulses  from  cell-body. 


Mcdul- 
lated 

Non- 
medul- 
lated 


Axis  cylinder  process. 

Medullary  sheath-function 

Neurilemma. 

Axis  cylinder  process. 
Neurilemma. 


I  Protection. 

\  Non-conduction. 


Nodes   of 
Ranvier 


■  Ring-like  constrictions  in  medullated  fibres,  due  to  absence  of 
medullary  sheath. 
Function  —  Render  easier  the  passage  of  blood-plasma  to 
fibre. 


Collaterals  —  Minute  side  branches  given  off  from  axis  cylinder  processes, 
usually  at  nodes  of  Ranvier. 


Chap.  XIX] 


SUMMARY 


403 


Nerve- 
endings 


Nerve- 
impulse 


1.  End  arborizations 


2. 


3. 


Inter-epithelial  arborizations  ( 
Organules 


terminations  in  brain  or  cord. 

terminations   of    sensory 
fibres  at  the  periphery 
J      of  the  body. 
Motor  plates  —  terminations  of    motor    nerve-fibres    in 

voluntary  muscle. 
Plexus  —  terminations  of  motor  nerve-fibres  in  involun- 
tary muscle. 
J  Nature  not  positively  known. 
I  Presumably  a  physical  molecular  vibration. 


Classifi- 
cation  of 
Nerve- 
fibres 


Efferent 


Excitatory 


,  Inhibitory 


'  Excitatory 


Afferent 


.  Inhibitory 


Reflex 


Inhibito- 
I'eflex 


f  Motor 


,  Secretory 

Inhibito- 
motor 

Inhibito- 
secre- 
tory 


Sensory 


Motor. 

Vasomotor. 

Cardiomotor. 

Visceromotor. 

Pilomotor. 
'  Salivary. 

Gastric. 

Pancreatic. 

Sweat. 
(  Subdivisions    correspond- 
S      ing  to  the  varieties  of 
i      motor  fibres  above. 

Subdivisions  correspond- 
ing to  the  varieties  of 
secretory  fibres  above. 

Visual. 

Auditory. 

Olfactory. 

Gustatory. 

Pressure. 

Temperature. 

Pain. 

Hunger. 

Thirst,  etc. 
J  According  to  the  efferent 
\      fibres  affected. 

Inhibitory  effects  upon  the 
conscious  sensations  are 
not  demonstrated. 

The  reflex  fibres  that  cause 
unconscious  reflexes  are 
known  to  be  inhibited 
in  some  cases  at  least. 


404 


ANATOMY   FOR   NURSES 


[Chap.  XIX 


Speed 
Nerve- 
impulse 


of 


Afferent  fibre  —  140  ft.  per  second. 
Efferent  fibre  —  110  ft.  per  second. 
Light  —  186,000  miles  per  second. 
Sound  —  1100  feet  per  second. 

Cell-bodies. 


Varieties 
of   Nerve  < 
Tissue 


Gray 
matter 


White 
matter 


Nerve- 
trunks 


Dendrites. 

Commencement  of  axones. 
Collaterals. 
(  Brain. 
<  Spinal  cord. 
I  Ganglia. 
Consists  of  medullated  nerves. 
Brain. 
Spinal  cord. 
Ganglia. 
Nerve-trunks. 

Neuroglia  —  Special  tissue  found  in  brain  and  spinal  cord  — 
function  —  support. 


Consists  of ' 


Found  in 


Found  in 


Consist 
of 

Func- 
tion is 
connec- 
.  tion  of 


Bundles  of  nerve-fibres  bound  together  to  make 

funiculi. 
Funiculi  bound  together  to  make  nerve-trunks. 
Connective   tissue  surrounds  funiculi   and   nerve- 

trimks. 

1.  Different  parts  of  nervous  system. 

2.  Nerve-centres  and  the  viscera. 

3.  Nerve-centres  and  the  periphery. 

4.  Viscera  and  the  surface  of  the  body. 


Nerve- 
centres 


Vertebral 
Ganglia 


■  Groups  of  nerv^e-cells  exercising  control   over  some  definite 
function. 
Loca-      j  Brain, 
tion     1  Spinal  cord. 

Ganglia  —  Collection  of  nerve-cells. 

(  Twenty-four  on  either  side  of  spinal  column. 
Number  ^  ^      .     ,       ,     , 

I  One  in  front  of  coccyx. 

1.  With  each  other  by  ganglia  cords. 

2.  With  spinal  nerves  by  rami  communicantes. 
a.  Pass  directly  to  viscera. 

Con-        I  [  Great  splanchnic. 

nected     1  3.  With       b.  Converge  to  form  <  Small  splanchnic. 

viscera  I  I  Least  splanchnic. 

c.  Join  collaterals  and  plexuses. 

d.  Join  spinal  nerves. 


Chap.  XIXl 


SUMMARY 


405 


Collateral 
Ganglia 


Located  principally  in  thoracic  and  abdominal  cavities. 

(With  spinal  nerves. 
With  vertebral  ganglia. 
With  viscera. 
(Cardiac  plexus. 
Solar  plexus. 
Hypogastric  or  pelvic  plexus. 

Terminal  f  Located  on  walls  of  organs  themselves. 
Ganglia    \  Connected  with  collateral  ganglia. 

Sympathetic  Ganglia  are  found  in  the  medulla,  spinal  canal,  and  in  connec- 
tion with  some  of  the  cranial  nerves. 


Con- 
nected 

Form 


Distribu- 
tion of 
Sympa- 
thetic 
Nerves 


Spinal 
Cord 


To  the  heart. 

To  the  involuntary  muscles  of  the  blood-vessels,  Ijnuphatics, 

and  viscera. 
To  the  secretory  glands. 
To  some  of  the  special  senses. 

Located  in  spinal  canal. 

Extends  from  foramen  magnum  to  second  lumbar  vertebra, 
16-17  in.  long. 

(  Dura  mater  (outer). 
Meninges     <  Arachnoid  (middle). 

I  Pia  mater  (inner) . 

'  Gray  matter  in  form  of  butterfly. 

(Sensory. 
Motor. 
Mixed, 
f  Anterior  divides  front  portion  in  lateral  halves. 
1  Posterior  —  divides  back  portion  in  lateral  halves. 
Isthmus  —  connects  lateral  halves. 
Canal  —  centre  of  isthmus. 

1.  Conduction. 

2.  Reflex  action. 

3.  Automatism. 

4.  Inhibition. 
5-  Transference. 


Consists  of 


Fissures 


Functions 


406 


ANATOMY  FOR   NURSES 


[Chap.  XIX 


Spinal 
Nerves 


Number 


,  Variety 


Cervical 8  pairs. 

Thoracic 12  pairs. 

Lumbar 5  pairs. 

Sacral 5  pairs. 

Coccygeal       1  pair. 

31  pairs. 
Medullated. 

Mixed  (^J"f^^- 
1  Motor. 


Origin  —  two  roots 


Distribution 

trunks 


two 


Anterior  in  gray  matter  of  cord. 

Posterior  in  spinal  ganglia. 

Anterior,  supplies  extremities,  and  parts 

of  body  in  front  of  spine. 
Posterior,  supplies  muscles  and  skin  of 

back  of  head,  neck,  and  trunk. 


Located  in  cranial  cavnty. 

Covered  by  meninges  —  same  as  spinal  cord. 

J  Maile  —  49^  oz.  average. 

\  Female  —  44  oz.  average. 


Weight 


Medulla 


Cerebellum   < 


Divisions  < 


Description 


Function 


Description 


Function 


f 


Pons  Varolii 


Description 


Function 


Cerebrum 
hemi- 
spheres 


Description  { 


'  Oblong-shaped  mass,  upward 

continuation  of  cord. 

Gray  matter  in  interior. 

.  "VMiite  matter  on  exterior. 

{Respirator}-  centres. 
Accelerator  centre  for  heart. 
Vasomotor  centres, 
f  Flat     oblong-shaped     mass, 

overhangs  medulla. 
I  3-4^  in.  transversely. 
I  2-2 1  from  before  backward. 
Gray  matter  on  exterior. 
White  matter  in  interior. 
f  Coordination. 
i  Maintenance  of  equilibrium. 
■  A  bridge  of  nerve-fibres  con- 
necting two  halves  of  cere- 
bellum and  also  medulla 
\\-ith  cerebrum. 
Connect  two  halves  of  cere- 
bellum. 
j  Connect   medulla   and   cere- 
l      brum. 

f  Egg-shaped  or  ovoidal. 
!  Fills  upper  portion  of  skull. 


Gray  matter 
on  outside 


r  Fissures. 

\  Sulci. 

I  Convolutions. 


Chap.  XIX] 


SUMMARY 


407 


<  <;  Divisions 


Description 


Fissures 


Ventricles  < 


f  f  f  White  matter  on  inside. 

Great      longitudi- 
nal fissure. 
Transverse  fissure. 
Rolandic. 
Sylvian. 

Parieto-occipital. 
Frontal. 
Parietal. 
Cerebrum   2  Lobes        {  Occipital, 

hemi-         {  I  Temporal, 

spheres      {  i  Central. 

Fourth  ventricle. 
Third  ventricle. 
2  lateral  ventricles. 
^  Fifth  ventricle, 
f  Motion. 
Sensation. 
Functions     {  Speech. 
Hearing. 
[  Memory  and  higher  functions. 

Motor  area  —  in  front  of  Fissure  of  Rolando. 

Visual  —  occipital  lobe. 

Auditory  —  superior  part  of  the  temporal 
Sense  areas  ]       lobe. 

^   '        ^  >  anterior  part  of  temporal  lobe. 
I  Gustatory]  ^  ^ 

Association  areas  —  parts  of  the  cerebral  cortex  which  are 
not  the  location  of  special  centres. 

I.  Olfactory. 
II.  Optic. 

III.  Motor  oculi. 

IV.  Pathetic. 
V.  Trifacial. 

VI.  Abducens. 
VII.  Facial. 
VIII.  Auditory. 
IX.  Glossopharyngeal. 
X.  Pneumogastric. 
XL  Spinal  accessory. 
XII.  Hypoglossal. 

Reflex  Act  —  Involuntary  activity  that  is  the  result  of  stimulation  by 
motor  nerve-fibres.  Impulses  are  transferred  from  sensory  fibres  and 
activate  the  motor  fibres. 


Names  of 
Areas 


Cranial  Nerves  < 


CHAPTER   XX 

INTERNAL   AND    EXTERNAL    SENSES:    TASTE,    SMELL,    HEARING. 

AND    SIGHT 

Definition  of  sensation,  —  Sensation  is  defined  as  perception 
through  the  sense  organs,  and  is  the  result  of  stimulation  of  these 
organs. 

Organs  necessary  for  sensation.  —  A  peripheral  organ  for  the 
reception  of  a  stimulus,  a  nerve  for  its  conduction,  and  a  centre 
in  the  brain  for  the  perception  and  interpretation  are  the  three 
essential  parts  of  a  sense  organ.  It  is  by  means  of  impressions 
received  by  the  peripheral  organs  and  conducted  by  the  nerves 
to  the  brain  that  the  mind  is  able  to  control  the  body  and  to  take 
cognizance  of  the  external  world. 

Where  sensations  are  interpreted.  —  Sensations  are  felt  and 
interpreted  in  the  brain.  Our  habit  of  projecting  sensations  to 
the  part  that  is  stimulated,  tends  to  obscure  this  fact.  In  reality 
we  see  and  hear  with  our  brains,  because  the  eye  and  ear  serve 
only  as  end  organs  to  receive  the  stimulus  which  must  be  carried 
to  the  brain  and  interpreted  before  we  do  see  or  hear. 

CLASSIFICATION  OF  SENSATIONS 

Sensations  were  formerly  classified  into  two  groups,  i.e.  special 
and  common.  The  special  senses  were  sight,  hearing,  touch, 
taste,  and  smell.  All  other  sensations  were  grouped  as  common. 
A  more  recent  classification  is  dependent  on  the  part  of  the  body 
to  which  the  sensation  is  projected,  and  the  two  groups  are  named : 
(1)  internal  or  interior  senses,  and  (2)  external  or  exterior  senses. 
These  classifications  have  much  in  common,  but  differ  slightly. 

Internal  or  interior  senses  are  those  in  which  the  sensations  are 
projected  to  the  interior  of  the  body.  It  is  by  means  of  these 
senses  that  we  acquire  a  knowledge  of  the  condition  of  our  body. 
They  include  hunger,  thirst,  pain,  muscular  sense,  fatigue,  and  vari- 

408 


Chap.  XX]     INTERNAL  AND   EXTERNAL   SENSES       409 

ous  obscure  sensations  which  proceed  from  the  viscera  and  give  us 
the  feehng  of  well-being  or  the  reverse,  also  the  desire  for  defecation 
or  urination. 

External  or  exterior  senses  are  those  in  which  the  sensations  are 
projected  to  the  exterior  of  the  body.  They  form  the  means  by 
which  we  become  acquainted  with  the  outside  world.  They 
include  pressure  and  temperature  sense,  taste,  smell,  hearing,  and 
sight.  Even  this  classification  is  not  absolutely  distinctive,  as 
some  sensations  may  be  projected  either  to  the  interior  or  exterior 
of  the  body.     Temperature  and  pain  are  examples  of  this  class. 

Hunger.  —  Hunger  occurs  normally  at  a  certain  time  after  meals 
and  is  usually  projected  to  the  region  of  the  stomach.  It  is  pre- 
sumably due  to  contractions  of  the  empty  stomach,  which  stimu- 
late the  nerves  distributed  to  the  mucous  membrane.  In  abnormal 
conditions  the  stomach  need  not  be  empty,  for  it  must  be  remem- 
bered that  physiologically  food  is  not  considered  as  being  inside  the 
body  until  it  ha.s  been  digested  and  absorbed.  Thus  a  diabetic 
may  feel  very  hungry,  although  he  has  within  a  short  time  partaken 
of  a  huge  meal. 

Thirst.  —  This  sensation  is  projected  to  the  pharynx.  We 
know  very  little  about  the  nervous  mechanism  involved,  but  it  is 
thought  that  when  the  water  content  in  the  tissues  falls  below  a 
certain  amount  the  sensory  nerve  fibres  in  the  pharynx  are  stimu- 
lated and'  produce  the  sensation  of  thirst.  The  sense  of  thirst 
is  more  imperative  than  that  of  hunger ;  a  person  can  live  several 
days  without  food,  provided  he  has  water,  but  if  this  latter  is 
denied,  he  will  soon  die  of  exhaustion. 

Pain.  —  The  sensation  of  pain  is  thought  by  some  authorities 
to  be  due  to  stimulation  of  special  nerves  that  give  rise  to  the 
sense  of  pain. 

Other  authorities  question  the  existence  of  special  nerves  for 
thivs  sense,  and  think  it  is  due  to  overstimulation  of  any  of  the 
sensory  nerves.  For  instance,  extreme  pressure  or  extremes  of 
temperature  cause  overstimulation  of  the  nerves  of  pressure  or 
temperature,  and  the  result  is  painful. 

Muscular  sense.  —  The  end  organs  of  the  muscular  sense  are 
situated  in  the  tendons  and  between  the  fibres  of  the  muscles. 
They  convey  to  us  the  sense  of  resistance  in  the  muscles  when 
we   attempt   to    lift   anything.      This    is    the   muscular   sense. 


410  ANATOMY   FOR   NURSES  [Chap.  XX 

Through  it  precision  of  effort  is  rendered  possible ;  for  by  it  we 
learn  to  adjust  the  force  exerted  to  the  weight  of  the  object  to 
be  lifted.  Thus  the  function  of  muscular  sense  is  to  enable  us 
to  estimate  weight  or  resistance.  It  also  aids  in  preserving 
equilibrium  and  in  coordinating  muscular  action. 

Fatigue.  —  Prolonged  or  extreme  muscular  exercise  results  in 
the  loss  of  nutrient  material  and  the  accumulation  of  waste  prod- 
ucts in  the  muscles.  These  chemical  changes  alter  the  stimula- 
tion of  the  nerves  connected  with  muscular  sense,  and  the  sensa- 
tion of  fatigue  results. 

Visceral  sensations.  —  Sensations  which  give  rise  to  the  feeling 
of  well-being  or  the  reverse,  also  to  the  acts  of  vomiting,  coughing, 
defecation,  or  urination,  are  caused  by  stimulation  of  the  sensory 
nerves  contained  in  the  part  of  the  body  immediately  concerned 
in  the  state  or  act  in  question. 

The  sense  of  pressure  or  touch.  —  The  nerves  connected  with 
the  sense  of  pressure  or  touch  are  distributed  over  the  entire  sur- 
face of  the  body,  being  more  or  less  numerous  in  all  parts  of  the  true 
skin  and  the  adjoining  mucous  membrane.  They  end  in  two 
ways:  (1)  in  a  ring  surrounding  a  hair  follicle,  so  that  pressure 
exerted  upon  the  hair  stimulates  these  end  organs,  and  (2)  in 
parts  of  the  body  where  there  are  no  hair  follicles,  in  the  tactile  or 
Meissner  corpuscles,  which  are  also  stimulated  by  pressure.  The 
distribution  of  these  nerves  is  not  uniform.  They  are  abundant 
and  the  pressure  points  are  very  close  together  on  the  lips  and  the 
tip  of  the  tongue,  also  in  parts  of  the  hands  and  feet  in  which  a 
delicate  sense  of  pressure  is  present. 

The  temperature  sense.  —  In  addition  to  the  end  organs  of  the 
sense  of  touch,  there  are  also  structures  in  the  skin  which  are  only 
stimulated  by  changes  in  temperature.  These  structures  are  of 
two  kinds  :  hot  and  cold  spots,  stimulation  of  one  causing  the  feel- 
ing of  heat ;   stimulation  of  the  other,  the  feeling  of  cold. 

In  addition  to  heat  and  cold  these  end  organs  are  stimulated  by 
other  substances,  i.e.  menthol  stimulates  the  cold  spots  and  gives 
rise  to  a  sensation  £)f  cold,  carbon  dioxide  stimulates  the  warm 
spots  and  gives  rise  to  a  sensation  of  heat,  while  certain  mechanical 
and  electrical  stimuli  will  cause  a  sensation  of  cold  on  a  cold  spot 
and  of  heat  upon  a  warm  spot. 

The  hot  and  cold  spots  and  the  pressure  points  can  be  located 


Chap.  XX]     INTERNAL  AND   EXTERNAL   SENSES      411 

by  passing  a  metallic  point  slowly  over  the  skin.  At  certain  points 
a  feeling  of  contact  or  pressure  will  be  experienced,  and  at  other 
points  a  feeling  of  cold  or  heat,  depending  on  whether  the  tempera- 
ture of  the  instrument  is  higher  or  lower  than  that  of  the  skin. 

TASTE 

Necessary  conditions.  —  Aside  from  the  conditions  which  are 
always  necessary  for  sense-perception,  —  viz.  proper  organs  for 
receiving,  communicating,  and  perceiving  the  sensory  impulse,  — 
there  must  be  present  a  sapid  substance  which  must  be  in  solu- 
tion. The  solution  in  the  case  of  dry  substances  is  effected  by 
saliva.  It  is  also  necessary  that  the  surface  of  the  organs  of  taste 
shall  be  moist.  The  substances  which  excite  the  special  sensa- 
tion of  "  taste  "  act  by  producing  a  change  in  the  terminal  fila- 
ments of  the  gustatory  nerve  (branch  of  the  glossopharyngeal) 
and  this  change  furnishes  to  it  the  required  stimulant. 

Organs  of  taste.  —  The  special  organs  of  the  sense  of  taste  are 
end  organs  of  nerve  filaments  w'hich  are  derived  from  the  seventh 
and  ninth  cranial  nerves.  These  end  organs  are  called  taste  buds 
and  are  situated  chiefly  on  the  surface  of  the  tongue,  though  there 
are  some  of  these  organs  scattered  over  the  soft  palate,  fauces, 
tonsils,  and  pharynx. 

The  tongue.  —  The  tongue  is  a  freely  movable  muscular  organ 
consisting  of  two  distinct  halves  united  in  the  centre.  The  base 
or  root  of  the  tongue  is  directed  backward  and  is  attached  to  the 
hyoid  bone  by  numerous  muscles.  It  is  connected  with  the  epi- 
glottis by  three  folds  of  mucous  membrane,  and  with  the  soft 
palate  by  means  of  the  anterior  pillars  of  the  fauces. 

PapillcB  of  the  tongue.  —  The  tongue  is  covered  and  lined  with 
mucous  membrane.  The  mucous  membrane  on  the  under  surface 
is  similar  to  that  lining  the  rest  of  the  mouth,  but  the  mucous 
membrane  on  the  upper  surface  is  studded  with  papillae  which  pro- 
ject as  minute  prominences  and  give  the  tongue  its  characteristic 
rough  appearance.     Of  these  papillae  there  are  three  varieties :  — 

(1)  Circum vallate  (walled  in)  papillae  are  the  largest,  are  circu- 
lar in  shape,  and  form  a  V-shaped  row  near  the  root  of  the  tongue, 
with  its  open  angle  turned  toward  the  lips.  They  serve  to  secrete 
mucus  and  contain  taste  buds  in  which  the  filaments  of  the  glosso- 
pharj^ngeal  nerve  terminate. 


412 


ANATOMY  FOR  NURSES 


[Chap.  XX 


(2)  Fungiform  papilla'  are  the  next  in  size,  and  are  so  named 
because  they  resemble  fungi  in  shape.  They  are  found  principally 
on  the  tip  and  sides  of  the  tongue.  Each  fungiform  papilla?  con- 
tains a  loop  of  capillaries  and  a  nerve-fibre  derived  from  the  glosso- 
pharyngeal nerve. 


Fig.  191.  —  The  Upper  Surface  of  tuk  i  onhue.     1,  2,  circumvallate  papillae ; 
3,  fungiform  papilla? ;    4,  filiform  papillae ;    6,  mucous  glands.     (Sappey.) 

(3)  Filiform  papillae  are  the  smallest  and  most  numerous. 
They  are  found  all  over  the  tongue,  except  at  the  root,  and  bear 
on  their  free  surface  delicate  hair-like  processes  which  seem  to  be 
specially  connected  with  the  sense  of  touch,  which  is  very  highly 
developed  on  the  tip  of  the  tongue. 

Nerve  supply  of  the  tongue.  —  The  nerve-fibres  which  terminate 
in  the  taste  buds  are :  (1)  filaments  of  the  lingual  nerve,  which  is  a 


Chap.  XX]     INTERNAL   AND   EXTERNAL  SENSES      413 

branch  of  the  fifth  or  trifacial,  (2)  filaments  of  the  chorda  tympani, 
a  branch  of  the  seventh  or  facial,  and  (3)  filaments  of  the  ninth 
or  glossopharyngeal  nerve. ^  The  twelfth  or  hypoglossal  nerve  is 
distributed  to  the  tongue,  but  is  a  motor  nerve  and  is  not  concerned 
in  the  sense  of  taste  or  touch. 

Other  sensations  in  the  tongue. — The  sense  of  touch  is  very 
highly  developed  here,  and  with  it  the  sense  of  temperature,  pain, 
etc. ;  upon  these  tactile  and  muscular  senses  to  a  great  extent 
depend  the  accuracy  of  the  tongue  in  many  of  its  important  uses  — 
speech,  mastication,  deglutition,  sucking. 

We  often  confound  taste  with  smell.  Substances  which  have 
a  strong  odor,  such  as  onions,  are  smelled  as  we  hold  them  in  our 
mouths ;  and  if  our  sense  of  smell  is  temporarily  suspended,  as  it 
sometimes  is  by  a  bad  cold  in  the  head,  we  may  eat  garlic  and 
onions  and  not  taste  them.  Hence  the  philosophy  of  holding 
the  nose  when  we  wish  to  s\^allow  a  nauseous  dose. 

SMELL 

Necessary  conditions.  —  The  first  essentials  are  a  special  nerve 
and  nerve-centre,  the  changes  in  whose  condition  are  perceived 
as  sensations  of  odor.  No  other  nerve  structure  is  capable  of 
such  sensations,  even  when  acted  on  by  the  same  cause.  The 
special  organs  for  this  sense  must  be  in  their  normal  condition, 
and  a  stimulus  (odor)  must  be  present  to  excite  them. 

Odors  are  caused  either  by  minute  particles  of  solid  matter  or 
by  gases  which  are  in  the  atmosphere,  and  they  must  be  capable 
of  solution  in  the  mucus  of  the  pituitary  membrane.  Odorous 
particles  in  the  air,  passing  through  the  lower,  wider  air  passages, 
pass  by  diffusion  into  the  higher,  narrower,  nasal  chambers, 
and  falling  on  the  membrane  which  is  provided  with  olfactory 
nerve-endings,  produce  sensory  impulses,  which,  ascending  to 
the  brain,  give  rise  to  the  sensation  of  smell. 

If  we  wish  to  smell  anything  particularly  well,  we  sniff  the  air 
up  into  the  higher  nasal  chambers,  and  thus  bring  the  odorous 
particles  more  closely  into  contact  with  the  olfactory  nerves. 

Each  substance  we  smell  causes  its  own  particular  sensation, 
and  we  are  not  only  able  to  recognize  a  multitude  of  distinct 

1  This  is  the  generally  accepted  view,  but  other  statements  may  be  found  in  the 
various  text-books. 


414 


ANATOMY  FOR  NURSES 


[Chap.  XX 


odors,  but  also  to  distinguish  individual  odors  in  a  mixed  smell. 
The  sensation  takes  some  time  to  develop  after  the  contact  of 
the  odorous  stimulus,  and  may  last  a  long  time.  When  the  stim- 
ulus is  repeated,  the  sensation  very  soon  dies  out,  the  sensory 
terminal  organs  quickly  becoming  exhausted.^ 

Olfactory  nerves.  —  The  olfactory  nerves  are  the  special  nerves 
of  the  sense  of  smell,  and  are  spread  out  in  a  fine  network  over 

the  surface  of  the  superior  tur- 
binated processes  of  the  ethmoid 
bone  and  on  the  upper  third  of 
the  septum.  The  nerves  end  in 
special  organs  known  as  olfac- 
tory cells,  which  lie  under  the 
epithelium,  but  send  prolonga- 
tions between  the  mucous  cells 
to  the  surface.  The  central  por- 
tions of  the  olfactory  cells  are 
prolonged  as  nerve-fibres  into 
a  mass  of  gray  matter,  called 
the  olfactory  bulb,  which  rests 
upon  the  cribriform  plate  of  the 


The  nerves  which  ramifv  over 


Fig.  192.  —  Vertic.vl  Longitudinal 
Section  or  Nas.^.l  Cavity.     1,  olfactory    ethmoid  bonC. 
nerve  ;    v,  branch  of  fifth  nerve  ;  h,  hard 
palate. 

the  lower  part  of  the  lining 
membrane  of  the  nasal  cavity  are  branches  of  the  fifth  or  tri- 
geminal nerve.  These  nerves  furnish  the  tactile  sense  and  enable 
us  to  perceive,  by  the  nose,  the  sensations  of  cold,  heat,  tickling, 
pain,  and  tension  or  pressure.  It  is  this  nerve  which  is  affected 
when  strong  irritants,  such  as  ammonia  or  pepper,  are  appreciated 
by  the  nose. 

HEARING 

The  auditory  apparatus  consists  of  :  (1)  the  external  ear ;  (2)  the 
middle  car ;    (3)  the  internal  ear ;   and  (4)  the  auditory  nerve. 

External  ear.  —  The  external  ear  consists  of  an  expanded  por- 
tion named  pinna,  or  auricle,  and  the  auditory  canal,  or  meatus. 

»  This  accounts  for  the  fact  that  one  may  easily  become  accustomed  to  foul  odors, 
and  is  of  special  importance  to  nurses.  Foul  odors  are  quickly  noticed  by  any 
one  coming  into  a  sick  room  from  out  of  doors,  but  a  nurse  who  is  in  the  sick  room 
constantly  may  become  accustomed  to  such  odors.  Hence  the  importance  of  act- 
ing on  the  first  sensation  of  a  disagreeable  odor. 


Chap.  XX]     INTERNAL  AND  EXTERNAL  SENSES      415 

The  auricle,  except  the  lower  portion,  consists  of  a  frame- 
work of  cartilage,  containing  some  fatty  tissue  and  a  few 
muscles.  In  the  lower  portion,  which  is  called  the  lobe, 
the  cartilage  is  replaced  by  connective  tissue.  The  auricle  is 
covered  with  skin,  and  joined  to  the  surrounding  parts  by 
ligaments  and  a  few  muscular  fibres.  It  is  very  irregular  in 
shape,  and  appears  to  be  an  unnecessary  appendage  to  the  organ 
of  hearing,  except  that  the  central  depression,  the  concha,  serves 
to  some  extent  to  collect  sound-waves,  and  to  conduct  them  into 
the  auditory  canal. 

The  auditory  canal  is  a  tubular  passage,  about  an  inch  (25  mm.) 
in  length,  leading  from  the  concha  to  the  drum-membrane.     The 


Fig.  193.  —  Semi-diagrammatic  Section  through  the  Right  Ear.  M, 
concha ;  G,  the  external  auditory  canal ;  T,  tympanic,  or  drum-membrane ;  P, 
tympanum,  or  middle  ear  ;  o,  oval  window  ;  r,  round  window.  Extending  from  T 
to  o  is  seen  the  chain  of  the  tympanic  bones ;  R,  Eustachian  tube ;  V,  B,  S,  bony 
labyrinth ;  V,  vestibule ;  B,  semicircular  canal ;  S,  cochlea ;  b,  I,  v,  membranous 
labyrinth  in  semicircular  canal  and  in  vestibule.  A,  auditory  nerve  dividing  into 
branches  for  vestibule,  semicircular  canal,  and  cochlea. 


exterior  portion  of  the  wall  of  the  auditory  canal  consists  of  carti- 
lage, which  is  continuous  with  that  of  the  auricle ;  the  posterior 
portion  is  hollowed  out  of  the  temporal  bone.  This  canal  is  slightly 
curved  upon  itself  so  as  to  be  higher  in  the  middle  than  at  either 
end,  and  its  direction  is  forward  and  inward.  Lifting  the  auricle 
upward  and  backward  tends  to  straighten  the  canal ;  except  in  the 
case  of  children  it  is  best  straightened  by  drawing  the  auricle 


416  ANATOiMY   FOR  NURSES  [Chap.  XX 

downward  and  backward.  It  is  lined  by  a  prolongation  of  the 
skin,  which  in  the  outer  half  of  the  canal  is  very  thick  and  not  at 
all  sensitive,  and  in  the  inner  half  is  thin  and  highly  sensitive. 
Near  the  orifice  the  skin  is  furnished  with  a  few  hairs,  and  far- 
ther inward  with  modified  sweat-glands,  the  ceruminous  glands, 
which  secrete  a  yellow,  pasty  substance  resembling  wax.  This 
wax  is  thought,  to  be  offensive  to  insects,  and  consequently  a 
defence  against  their  intrusion. 

Middle  ear.  —  The  middle  ear,  or  t\Tnpanum,  is  a  small,  ir- 
regular bony  cavity,  situated  in  the  petrous  portion  of  the  temporal 
bone,  and  lined  with  mucous  membrane.  It  is  separated  from  the 
external  auditory  canal  by  the  drum-membrane  (membrana 
tympani),  and  from  the  internal  ear  by  a  very  thin,  bony  wall 
in  which  there  are  two  small  openings  covered  with  membrane 
—  the  oval  window,  or  fenestra  ovalis,  and  the  round  window, 
or  fenestra  rotunda.  The  cavity  of  the  middle  ear  is  so  small 
that  probably  five  or  six  drops  of  water  would  completely  fill  it. 
It  communicates  below  with  the  pharynx  by  the  small  passage 
called  the  Eustachian  tube.^ 

The  function  of  this  tube  is  to  ventilate  this  cavity  and  keep  the 
atmospheric  pressure  equal  on  each  side  of  the  drum-membrane. 
The  middle  ear  also  communicates  above  with  a  number  of  bony 
cavities  in  the  mastoid  portion  of  the  temporal  bone.  These 
cavities,  called  mastoid  cells,  are  lined  with  mucous  membrane, 
which  is  continuous  with  that  covering  the  cavity  of  the  tympa- 
num. 

Membrana  tympani  (membrane  of  the  drum).  —  It  is  a  tough, 
fibrous  membrane  set  in  the  bony  opening  of  the  external  audi- 
tory canal.  The  degree  of  tension  of  the  membrane  is  regulated 
by  the  tensor  tympani  muscle.  This  muscle  is  lodged  in  a  bony 
canal  that  is  above  and  parallel  with  the  Eustachian  tube. 

Ossicles.  —  Stretching  across  the  tympanic  cavity  is  a  chain 
of  tiny,  movable  bones,  three  in  number,  and  named  from  their 
shape  the  malleus,  or  hammer,  the  incus,  or  anvil,  and  the  stapes, 
or  stirrup.  The  handle  of  the  hammer  is  attached  to  the  drum- 
membrane,  and  the  opposite  end  or  head  of  the  hammer  is  at- 

'  This  direct  connection  between  the  ear  and  the  pharynx  is  one  of  the  impor- 
tant reasons  for  the  frequent  cleansing  of  the  mouth  necessary  in  infectious  and 
contagious  diseases.  The  Eustachian  tube  forms  a  passageway  for  germs  to  travel 
from  the  mouth  to  the  middle  ear  and  there  cause  various  infections. 


Chap.  XX]     INTERNAL  AND   EXTERNAL  SENSES      417 

tached  to  the  base  of  the  anvil.  The  long  process  of  the  anvil  is 
attached  to  the  stapes,  and  the  footpiece  of  the  stapes  is  attached 
to  the  fibrous  membrane  that  is  stretched  across  the  oval  window. 
These  little  bones  are  held  in  position,  attached  to  the  drum-mem- 
brane, to  each  other,  and  to  the  membrane  of  the  oval  window  by 
minute  ligaments  and  muscles.  They  are  set  in  motion  with  every 
movement  of  the  drum-membrane.  Vibrations  of  the  mem- 
brane are  communicated  to  the  hammer,  taken  up  by  the  an^'il, 


Fig.  194.  —  Ossicles  of  the  Tympanum,  X  4.  I,  ossicles  of  the  left  ear ;  1, 
malleus;  2,  incus;  3,  stapes.  II,  ossicles  of  the  right  ear;  1,  malleus;  2,  long 
process ;  3,  handle ;  4,  long  process  of  the  incus ;  5,  short  process  of  the  incus ; 
6,  stapes.     (Flint.) 

and  transmitted  to  the  stirrup,  which  rocks  in  the  fenestra  ova- 
lis,  and  is  therefore  capable  of  transmitting  to  the  fluid  in  the 
cavity  of  the  labyrinth  the  impulses  which  it  receives. 

Internal  ear.  —  The  internal  ear,  or  labyrinth,  receives  the  ulti- 
mate terminations  of  the  auditory  nerve,  and  is,  therefore,  the 
essential  part  of  the  organ  of  hearing.  It  consists  of  a  bony 
labyrinth,  which  is  composed  of  a  series  of  peculiarly  shaped 
cavities,  hollowed  out  of  the  petrous  portion  of  the  temporal 
bone,  and  named  from  their  shape :  — 

(a)  The  vestibule. 

(6)  The  semicircular  canals. 

(c)  The  cochlea  (snail-shell). 
Within  the  bony  labyrinth  is  a  membranous  lab3rrinth,  which  is 
composed  of  a  series  of  sacs,  or  tubes,  fitting  more  or  less  closely 
within  the  vestibule,  semicircular  canals,  and  coclilea.     In  some 
2e 


418  ANATOMY   FOR   NURSES  [Chap.  XX 

places  it  is  attached  to  the  bone  by  bands  of  fibrous  tissue.  The 
cavity  within  the  membrane  is  filled  with  a  fluid  called  endolymph, 
and  the  space  between  the  membrane  and  the  bone  is  filled  with 
perilymph. 

The  vestibule  is  the  central  cavity  situated  between  the  cochlea 
in  front  and  the  semicircular  canals  behind.  It  communicates 
with  the  middle  ear  by  means  of  the  oval  window  in  its  outer  wall. 
The  vestibular  membrane  is  constricted  in  the  centre  so  that  it 


Fig.  196.  —  The  Left  Bony  Labyhinth  of  a  New-born  Child,  Forward  and 
Outward  View,  X  4.     From  a  photograph,  and  slightly  reduced. 

1,  the  wide  canal,  the  beginning  of  the  spiral  canal  of  the  cochlea  ;  2,  the  fenestra 
rotunda;  3,  the  second  turn  of  the  cochlea;  4,  the  final  half-turn  of  the  cochlea; 
5,  the  border  of  the  bony  wall  of  the  vestibule,  situated  between  the  cochlea  and 
the  semicircular  canals ;  6,  the  superior,  or  sagittal  semicircular  canal ;  7,  the 
portion  of  the  semicircular  canal  bent  outward  ;  8,  the  posterior,  or  transverse 
semicircular  canal ;  9,  the  portion  of  the  posterior  connected  with  the  superior  semi- 
circular canal ;  10,  point  of  junction  of  the  superior  and  the  posterior  semicircular 
canals ;  11,  the  ampulla  ossea  externa ;  12,  the  horizontal,  or  external  semicircular 
canal.     (Flint.) 

consists  of  two  small  sacs,  called  respectively  the  saccule  and  the 
utricle.  The  saccule  is  in  front  and  nearer  the  cochlea,  and  the 
utricle  is  back  and  nearer  the  semicircular  canals.  These  sacs 
are  connected  by  a  tube  called  the  endolymj)h  duct,  which  is 
shaped  like  an  inverted  Y  (X).  The  walls  of  these  sacs  contain 
numerous  columnar  cells  provided  with  stiff  hairs  which  project 
into  the  endol\-mph.  These  cells  are  in  relation  with  fibres  of  the 
vestibular  branch  of  the  auditory  nerve  and  serve  as  end  organs. 
Among  these  hair-cells  rest  several  small  crystals  of  calcium  car- 
bonate which  are  called  otoliths. 


Chap.  XX]     INTERNAL  AND   EXTERNAL  SENSES      419 

The  cochlea  opens  from  the  front  end  of  the  vestibule  and  saccule. 
It  resembles  a  snail  shell  and  consists  of  a  spiral  tube  of  two  and 
one-half  turns  around  a  central  pillar  called  the  modiolus. 

Projecting  from  the  modiolus  is  a  thin  lamina  or  plate  of  bone. 
At  its  outer  margin  this  lamina  connects  with  a  membrane  which 
extends  to  the  outer  wall  of  the  cochlea.  This  lamina  and  mem- 
brane divide  the  spiral  canal  into  two  passages  or  scahne.  The  lower 
portion  of  this  membrane  is  called  the  basilar  membrane,  and  con- 
sists of  a  network  of  fibres  which  forms  the  foundation  for  thou- 
sands of  cells  which  serve  as  the  end  organs  of  the  auditory  nerve. 
These  end  organs  constitute  a  structure  that  is  known  as  the  organ 
of  Corti.  They  receive  nerve-fibres  which  arise  in  the  ganglia  con- 
tained in  the  cavity  of  the  modiolus.  Both  the  modiolus  and  lam- 
ina are  pierced  by  numerous  openings  for  the  passage  of  these 
nerves. 

The  semicircular  canals  are  three  bony  canals  lying  above  and 
behind  the  vestibule,  and  communicating  with  it  by  five  openings, 
in  one  of  which  two  tubes  join.  They  are  known  as  the  posterior, 
vertical,  and  horizontal  canals,  and  their  position  is  such  that  each 
one  is  at  right  angles  to  the  other  two.  One  end  of  each  tube  is 
enlarged  and  forms  what  is  known  as  the  ampulla.  The  membrane 
of  the  ampulla  is  covered  with  cells  that  are  similar  to  those  found 
in  the  utricle  and  saccule.  These  hair-cells  serve  as  end  organs  for 
the  vestibular  branch  of  the  auditory  nerve. 

The  auditory  nerve.  —  The  eighth  or  auditory  nerve  is  a  sensory 
nerve  and  contains  two  distinct  sets  of  fibres,  which  differ  in  their 
function,  origin,  and  destination.  One  set  of  fibres  is  known  as 
the  cochlear  division  and  the  other  as  the  vestibular. 

The  fibres  of  the  cochlear  nerve  arise  from  bipolar  cells  that  are 
situated  in  the  modiolus  of  the  cochlea.  One  axis  cylinder  from 
each  cell  passes  through  the  foramina  of  the  modiolus  or  lamina, 
and  terminates  in  and  around  the  cells  that  constitute  the  organ 
of  Gorti.  The  other  axis  cylinder  passes  through  the  intepial 
auditory  meatus  to  a  portion  of  the  brain,  called  the  cochlear 
root  of  the  auditory  nerve.  This  root  is  located  at  the  lower  edge 
of  the  pons  Varolii.  The  nerve-fibres  which  pass  from  the  ear  to 
the  pons  or  from  the  pons  to  the  ear  are  not  continuous  strands, 
as  there  are  several  relays  of  ganglia  in  which  the  axones  of  one 
cell  interlock  with  the  dendrites  of  another  cell. 


420 


ANATOMY  FOR  NURSES 


[Chap.  XX 


The  fibres  of  the  vestibular  nerve  haw  their  orighi  in  the  gray 
matter  of  the  pons  \  arolii.  Some  of  these  fibres  extend  to  the 
cerebelkim  and  to  motor  centres  of  the  si)inal  nerves.  Other  fibres 
extend  to  tlie  vestibnle  and  are  (Hstril)uted  around  the  liair-eells 
of  the  saccule,  utricle,  and  the  ampulla  of  the  semicircuhir  canals. 
Physiology  of  hearing.  —  All  bodies  which  produce  sound  are 
in  a  state  of  vibration,  and  communicate  their  vibrations  to  the 
air  with  which  they  are  in  contact. 

When  these  air-waves,  set  in  motion  by  sonorous  bodies,  enter 
the  external  auditory  canal,  they  set  the  drum-membrane  vibrat- 
ing, stretched  membranes  taking  up  vibrations  from  the  air  with 
great  readiness.  These  vibrations  are  communicated  to  the  chain 
of  tiny  bones  stretched  across  the  middle  ear,  and  their  oscilla- 
tions cause  the  membrane  leading  into  the  internal  ear  to  be 
alternatively  pushed  in  and  drawn  out,  and  vibrations  are  in  this 
way  transmitted  to  the  perilymph.  The  movements  of  the  peri- 
lymph are  transmitted  to  the  basilar  membrane,  and  set  some  of 
the  strings  in  motion.  In  some  unknown  way  tliese  movements 
are  transmitted  to  the  hair-cells  and  through  them  to  the  nerve- 
fibres  at  their  base.  By  means  of  the  nerve-fibres  the  stimulus 
is  conveyed  to  the  brain  and'interpreted  there,  so  that  it  is  with 
the  brain  that  we  hear. 

The  sense  of  equilibrium.  —  Among  the  various  means  (such  as 

sight,  touch,  and  muscular  sense) 
whereby  we  are  enabled  to  maintain 
our  equilibrium,  coordinate  our  move- 
ments, and  become  aware  of  our  po- 
sition in  space,  one  of  the  most  im- 
portant is  the  action  of  the  vestibule 
and  semicircular  canals.  Though 
these  structures  are  found  in  the  inner 
ear  and  communicate  with  the  coch- 
lea, it  is  now  thought  that  they  are 
not  connected  with  the  sense  of  hear- 
ing. Just  how  they  perform  their 
function  is  not  known,  but  it  is 
thought  that  movements  of  the  head 
set  up  movement  in  the  endol^'mph  of  the  canal,  and  this  acts  as 
a  stimulus  to  the  nerve-endings  around  the  hair-cells. 


Fig.  196.  —  Diagram  show- 
ing Relative  Position  of  the 
Planes  in  which  the  Semi- 
circular Canals  Lie.  Rt., 
right  ear;  Lt.,  left  ear;  A.V., 
anterior  vertical  canal;  P.V., 
posterior  vertical  canal ;  H., 
horizontal  canal ;  a,  ampulla  of 
Rt.  anterior  vertical  canal ;  a', 
ampulla  of  Lt.  posterior  vertical 
canal. 


CiL\p.  XX]     INTERNAL  AND   EXTERNAL   SENSES      421 

The  canals  are  so  arranged  (Fig.  196)  that  any  movement  of 
the  head  causes  an  increase  in  the  pressure  of  the  endol;^Tiiph  in  one 
ampulla,  and  a  corresponding  diminution  in  the  ampulla  of  the 
parallel  canal  on  the  opposite  side.  Thus,  a  nodding  of  the  head 
to  the  right  would  cause  a  flow  of  the  endoh-mph  from  a  to  6  in 
the  right  anterior  vertical  canal,  but  fror&  h'  to  a'  in  the  left  poste- 
rior vertical  canal.  Hence  the  pressure  upon  the  hairs  is  decreased 
in  a,  but  increased  in  a'.  Such  stimulations  of  the  sensory  hairs 
are  transmitted  by  the  dendrites  of  the  vestibular  nerve,  through 
the  cell-bodies  of  the  vestibular  ganglion  and  the  axis  cylinders 
of  the  auditory  nerve,  to  the  pons  Varolii  and  thence  to  the  cere- 
bellum. It  is  thought  that  the  cerebellum  is  the  centre  in  the  brain 
which  interprets  and  adjusts  the  impulses  that  arise  from  stimula- 
tion of  the  sensory  nerves  concerned  with  muscular  sense.  It  is 
also  the  centre  that  interprets  and  adjusts  impulses  that  arise  from 
stimulation  of  the  vestibular  nerve-endings.  From  this  it  follows 
that  the  cerebellum  controls  equilibrium. 

SIGHT 

The  Adsual  apparatus  consists  of  the  eyeballs,  the  optic  nerves, 
and  the  nerve  centres  in  the  brain.  In  addition  to  these  essential 
organs,  there  are  accessory  organs  which  are  necessary  for  the 
protection  and  functioning  of  the  eyeball. 

Accessory  organs  of  the  eye.  —  Under  this  heading  we  class : 
(1)  eyebrows,  (2)  eyelids,  (3)  lacrimal  apparatus,  and  (4)  muscles 
of  the  eyeball. 

Eyebrows.  ^  The  eyebrows  are  composed  of  two  arched  emi- 
nences of  thickened  skin,  covered  with  hairs.  They  are  situated 
on  the  upper  border  of  the  orbits,  and  protect  the  eyes  from  too 
vivid  light. 

Eyelids.  —  The  eyelids  are  two  folds  projecting  from  above  and 
below  in  front  of  the  eye.  They  are  covered  externally  by  the 
skin,  and  internally  by  a  mucous  membrane,  the  conjunctiva, 
which  is  reflected  from  them  over  the  globe  of  the  eye.  They 
are  composed  for  the  most  part  of  connective  tissue,  which  is 
dense  and  fibrous  under  the  conjunctiva,  where  it  is  known  as 
the  tarsal  cartilage. 

Arranged  in  a  double  or  triple  row  at  the  margin  of  the  lids 
are  the  eyelashes ;    those  of  the  upper  lid  more  numerous  and 


422 


ANATOMY   FOR   NURSES 


[Chap.  XX 


longer  than  those  of  the  lower.  The  upper  lid  is  attached  to  a 
small  muscle  wliich  is  called  the  elevator  of  the  upper  lid  (levator 
palpebraB  superioris),  and  arranged  as  a  sphincter  around  both  lids 
is  the  orbicularis  palpebrarum  muscle,  which  closes  the  eyelids, 
and  is  the  direct  antagonist  of  the  elevator  of  the  upper  lid. 

The  slit  between  the  e*dges  of  the  lids  is  called  the  palpebral 
fissure.  It  is  the  size  of  this  fissure  which  causes  the  appearance 
of  large  and  small  eyes,  as  the  size  of  the  lobe  itself  varies  but 
little.  The  outer  angle  of  this  fissure  is  called  the  external  can- 
thus  ;  the  inner  angle,  the  internal  canthus. 

The  eyelids  are  obviously  provided  for  the  profection  of  the 
eye;  movable  shades  which  by  their  closure  exclude  light,  par- 
ticles of  dust,  and  other  injurious  substances. 

Tarsal  glands  (Meibomian  glands).  —  Embedded  in  the  tarsal 
cartilage  of  each  eyelid  is  a  row  of  elongated  sebaceous  glands, 

—  the  tarsal  ^  glands,  — 
the  ducts  of  which  open 
on  the  edge  of  the  eyelid. 
The  secretion  of  these 
glands  is  provided  to 
prevent  adliesion  of  the 
eyelids. 

Lacrimal  apparatus.  — 
This  apparatus  consists 
of :  (1)  the  lacrimal  gland, 
(2)  canaliculi,  (3)  lacrimal 
sac,  and  (4)  nasal  duct. 
The  lacrimal  gland  is  a 
compound  gland,  closely 
resembling  the  salivary 
glands  in  structure,  and 
is  lodged  in  a  depres- 
sion at  the  upper  and 
outer  angle  of  the  orbit.  It  consists  of  two  portions,  an  upper  por- 
tion about  the  size  and  shape  of  an  almond,  and  a  lower  portion 
consisting  of  a  group  of  small  glands  arranged  in  a  row.  These 
two  portions  are  only  partially  separated  by  a  fibrous  septum. 

'  By  everting  the  eyelids,  these  glands  may  be  seen  through  the  conjunctiva 
lying  in  parallel  rows. 


Fig.  197.  —  The  Lackimal  Apparatus. 
(Note  that  preference  is  given  to  the  spelling 
"lacrimal"  as  found  in  text,  instead  of  "lachry- 
mal" as  found  on  illustration.) 


Chap.  XX]    INTERNAL  AND  EXTERNAL  SENSES      423 

Seven  to  twelve  minute  ducts  lead  from  the  gland  to  the  surface 
of  the  conjunctiva  of  the  upper  lid.  The  secretion  (tears)  is 
usually  just  enough  to  keep  the  eye  moist,  and  after  passing  over 
the  surface  of  the  eyeball  is  sucked  into  two  tiny  canaliculi 
through  the  punctae  and  is  conveyed  into  the  lacrimal  sac,  which 
is  the  upper  dilated  portion  of  the  nasal  duct. 

The  nasal  duct  is  a  membranous  canal,  about  three-quarters 
of  an  inch  (19  mm.)  in  length,  which  extends  from  the  lacrimal 
sac  to  the  nose,  into  which  it  opens  by  a  slightly  expanded  orifice. 

The  tears  consist  of  water  containing  a  little  salt  and  albumin. 
They  are  ordinarily  carried  away  as  fast  as  formed,  but  under 
certain  circumstances,  as  when  the  conjunctiva  is  irritated,  or 
when  painful  emotions  arise  in  the  mind,  the  secretion  of  the 
lacrimal  gland  exceeds  the  drainage  power  of  the  nasal  duct, 
and  the  fluid,  accumulating  between  the  lids,  at  length  overflows 
and  runs  down  the  cheeks. 

The  conjunctiva.  —  The  conjunctiva  is  the  mucous  membrane 
which  lines  the  eyelids  and  is  reflected  over  the  front  of  the  eyeball. 
It  is  often  considered  part  of  the  lacrimal  apparatus  as  it  secretes 
a  fluid  like  that  of  the  lacrunal  gland. 

Muscles  of  the  eye.  —  For  purposes  of  description  the  muscles 
of  the  eye  are  divided  into  two  groups :  (1)  intrinsic,  and 
(2)  extrinsic.  The  intrinsic  muscles  are  the  ciliary  muscle,  and 
the  muscles  of  the  iris.  (See  page  426.)  The  extrinsic  muscles 
are  those  which  move  the  eyeball  and  include  the  four  straight, 
or  recti,  and  the  two  oblique.  They  have  been  described  in 
Chapter  VII. 

Nerves  of  the  eye.  —  The  nerves  which  are  supplied  to  the  eye 
are:   (1)  the  optic  nerve,  which  is  concerned  with  vision  only; 

(2)  the  motor  oculi  nerve  controls  the  internal  rectus,  the  superior 
rectus,   the   inferior  rectus,   and   the   inferior   oblique   muscles; 

(3)  the   pathetic   nerve    controls   the    superior   oblique  muscle; 

(4)  the  abducens  controls  the  external  rectus;  and  (5)  the 
ophthalmic,  which  is  a  branch  of  the  trifacial  nerve,  supplies  gen- 
eral sensation. 

The  orbits.  —  The  orbits  are  the  bony  cavities  in  which  the 
eyeballs  are  contained. 

Seven  bones  assist  in  the  formation  of  each  orbit,  namely,  frontal, 
malar,  maxilla,  palate,  etlmioid,  sphenoid,  and  lacrimal.     As  three 


424 


ANATOMY   FOR   NURSES 


[Chap.  XX 


of  these  bones  are  mesial  (frontal,  ethmoid,  and  sphenoid)  there 
are  only  eleven  bones  forming  both  orbits. 

The  orbit  is  shaped  like  a  four-sided  pyramid  ;  the  apex,  directed 
backward  and  inward,  is  pierced  by  a  large  opening  —  the 
optic  foramen  —  through  which  the  optic  nerve  and  the  ophthalmic 
artery  pass  from  the  cranial  cavity  to  the  eye.  A  larger  opening 
to  the  outer  side  of  the  optic  foramen  —  the  sphenoidal  fissure  — 
provides  a  passage  for  the  ophthalmic  vein  and  the  nerves  which 


SUPERIOR  RECTUS 


CHOROrO 


OPTIC  NERVE 


iNFERIOBRfCTUS 

Fig.  198.  —  Diagrammatic  Section  of  the  Eye.     (Flint.) 

carry  impulses  to  and  from  the  muscles,  i.e.  the  motor  oculi, 
the  pathetic,  the  abducens,  and  the  ophthalmic.  The  base  of  the 
orbit,  directed  outward  and  forward,  forms  a  strong,  bony  edge 
for  protecting  the  eyeball  from  injury. 

Each  orbit  averages  about  2  inches  (50  mm.)  in  depth,  is  lined 
with  fibrous  tissue,  and  contains  a  pad  of  fat,  which  serves  as  a 
support  for  the  eyeball.  A  condition  of  emaciation  is  usually 
accompanied  by  sunken  eyes,  which  results  from  the  absorption 
of  this  fat,  and  the  consequent  sinking  of  the  eyeballs  in  the  orbits. 
Between  the  pad  of  fat  and  the  eyeball  is  a  serous  sac  — =-  the 
capsule  of  Tenon  —  which  envelops  the  eyeball  from  the  optic 
nerve  to  the  ciliary  region  and  forms  a  socket  in  which  the  eyeball 
rotates.  This  sac  secretes  a  lubricating  fluid,  the  function  of 
which  is  to  prevent  friction  when  the  eyeball  moves. 


Chap.  XX]     INTERNAL  AND   EXTERNAL  SENSES      425 

The  eyebalL  —  The  eyeball  is  spherical  in  shape,  but  its  trans- 
verse diameter  is  less  than  the  antero-posterior,  so  that  it  projects 
anteriorly,  and  looks  as  if  a  section  of  a  smaller  sphere  had  been 
engrafted  on  the  front  of  it. 

The  eyeball  is  composed  of  three  coats,  or  tunics,  and  contains 
three  refracting  media  or  humors.     They  are  as  follows  :  — 

Tunics.  —  1.  Sclera  and  cornea. 

2.  Choroid,  ciliary  body,  and  iris. 

3.  Retina. 
Refracting  media.  —  1.  Aqueous. 

2.  Crystalline  lens  and  capsule. 

3.  Vitreous. 

The  sclera.  —  The  sclera,  or  "  white  of  the  eye,"  covers  the 
posterior  five-sixths  of  the  eyeball.  It  is  composed  of  a  firm, 
unyielding,  fibrous  membrane,  thicker  behind  than  in  front,  and 
serves  to  protect  the  delicate  structures  contained  within  it,  and 
maintain  the  shape  of  the  eyeball.  It  is  opaque,  white,  and 
smooth  externally,  and  behind  is  pierced  by  the  optic  nerve.  In- 
ternally it  is  stained  brown  where  it  comes  in  contact  with  the 
choroid  coat.  It  is  supplied  with  very  few  blood-vessels,  and  the 
existence  of  nerves  in  it  is  doubtful. 

The  cornea.  —  The  cornea  covers  the  anterior  sixth  of  the  eye- 
ball. It  is  directly  continuous  with  the  sclera,  which,  however, 
overlaps  it  slightly  above  and  below,  as  a  watch  crystal  is  over- 
lapped by  the  case  into  which  it  is  fitted.  The  cornea,  like  the 
sclera,  is  composed  of  fibrous  tissue,  which  is  both  firm  and  un- 
yielding, but,  unlike  the  sclera,  it  has  no  color,  and  is  perfectly 
transparent ;  it  has  been  aptly  termed  the  "  window  of  the  eye." 
The  cornea  is  well  supplied  with  nerves  and  lymph-spaces,  but  is 
destitute  of  blood-vessels,  so  that  it  is  dependent  on  the  lymph 
contained  in  the  lymph-spaces  for  nutriment. 

Choroid.  —  The  choroid,  or  vascular  coat  of  the  eye,  is  a  thin, 
dark  brown  membrane  lining  the  inner  surface  of  the  sclera.  It  is 
composed  of  delicate  connective  tissue,  the  cells  of  which  are  large 
and  filled  with  pigment,  and  it  contains  a  close  network  of  blood- 
vessels. The  pigment  cells  and  blood-vessels  render  this  mem- 
brane dark  and  opaque,  so  that  it  darkens  the  chamber  of  the  eye 
by  preventing  the  reflection  of  light.  It  extends  to  within  a  short 
distance  of  the  cornea. 


426 


ANATOMY  FOR  NURSES 


[Chap.  XX 


BADIATING  I 
VESSELS 
OF    IBIS       ' 


The  ciliary  body,  —  The  ciHary  body  is  located  between  the 
clioroid  and  tlie  iris,  and  contains  the  ciliary  processes,  and  the 

ciliary  muscle.  Just  behind 
the  edge  of  the  cornea,  the 
choroid  is  folded  inward  and 
arranged  in  radiating  folds, 
like  a  phiited  ruffle,  around 
tlie  lens.  There  are  about 
seventy  of  these  folds,  and 
they  constitute  the  ciliary 
processes.  They  are  well 
supplied  with  nerves  and 
blood-vessels,  and  also  support 
a  muscle,  the  ciliary  muscle. 
The  fibres  of  this  muscle 
arise  from  the  sclera  near 
the  cornea,  and  extending 
backward  are  inserted  into 
the  outer  surface  of  the  ciliary 
processes  and  the  choroid. 
The  action  of  this  muscle 
determines  the  position  of 
the  lens. 

Iris.  —  The  iris  (iris,  rain- 
bow) is  a  colored,  fibro-muscu- 
lar  curtain  hanging  in  front  of 
the  lens  and  behind  the  cornea. 
It  is  attached  at  its  circumference  to  the  ciliary  processes,  with 
wliich  it  is  practically  continuous,  and  is  also  connected  to  the 
sclera  and  cornea  at  the  point  where  they  join  one  another. 
Except  for  this  attachment  at  its  circumference,  it  hangs  free 
in  the  interior  of  the  eyeball.  In  the  middle  of  the  iris  is  a  cir- 
cular hole  —  the  pupil  —  through  which  light  is  admitted  into 
the  eye  chamber.  The  iris,  like  the  choroid,  is  composed  of  con- 
nective tissue  containing  a  large  number  of  pigment  cells  and 
numerous  blood-vessels.  It  contains,  in  addition,  two  sets  of  mus- 
cular fibres.  One  set  is  arranged  like  a  sphincter  with  its  fibres 
encircling  the  pupil,  and  is  called  the  contractor  of  the  pupil.  The 
other  set  consists  of  fibres  which  radiate  from  the  pupil  to  the 


Fig.  199.  —  Segment  of  the  Iris, 
Ciliary  Body,  and  Choroid.  Viewed 
from  the  internal  surface.     (Gerrish.) 


Chap.  XX]     INTERNAL  AND   EXTERNAL  SENSES      427 


outer  circumference  of  the  iris,  and  is  called  the  dilator  of  the  pupil. 
The  action  of  these  muscle  fibres  is  antagonistic. 

The  posterior  surface  of  the  iris  is  covered  by  a  thick  layer  of 
pigment-cells  designed  to  darken  the  curtain  and  prevent  the  en- 
trance of  light.     The  _^ 

anterior  surface  of  the 
iris  is  also  covered  with 
pigment  cells,  and  it  is 
chiefly  these  latter 
which  cause  the  beau- 
tiful colors  seen  in  the 
iris.  The  different  col- 
ors of  eyes,  however, 
are  mainly  due  to  the 
amount,  and  not  to  the 
color,  of  the  pigment 
deposited. 

Function  of  the  iris. 
—  The  function  of  the 
iris  is  to  regulate  the 
amount  of  light  enter- 
ing the  eye,  and  thus 
assist  in  obtaining  clear 
images.     It  is  enabled 

to  perform  this  function  by  the  action  of  the  muscles  described 
above,  as  their  contraction  or  relaxation  determines  the  size  of  the 
pupil.  When  the  eye  is  accommodated  for  a  near  object,  or 
stimulated  by  a  bright  light,  the  sphincter  muscle  contracts  and 
diminishes  the  size  of  the  pupil.  When,  on  the  other  hand,  the 
eye  is  accommodated  for  a  distant  object,  or  the  light  is  dim,  the 
dilator  muscle  contracts,  and  the  pupil  is  pulled  wider  open. 

Retina.  —  The  retina,  the  innermost  coat  of  the  eyeball,  is 
the  most  essential  part  of  the  organ  of  sight,  since  it  is  the  only 
one  directly  sensitive  to  light.  The  sclera  is  the  protective,  the 
choroid  the  vascular,  or  nutritive,  and  the  retina  is  the  visual, 
or  perceptive,  layer  of  the  eyeball.  It  is  a  transparent  mem- 
brane of  a  grayish  color  that  is  formed  by  the  spreading  out  or 
expansion  of  the  optic  nerve.  It  is  situated  between  the  inner 
surface  of  the  choroid  and  the  outer  surface  of  the  vitreous  humor, 


Fig.  200.  —  Choroid  Membrane  and  Iris 
exposed  by  the  removal  of  the  sclera  and 
Cornea.  Twice  the  natural  size,  d,  one  of  the 
segments  of  the  sclera  thrown  back  ;  I  and  k,  iris  ; 
c,  ciliary  nerves  ;  e,  one  of  the  veins  of  the  choroid. 
The  ciliary  muscle  is  crossed  by  the  line  from  k,  and 
should  be  represented  as  radiating.     (Collins.) 


428 


ANATOMY   FOR  NURSES 


[Chap.  XX 


and  extends  from  the  entrance  of  the  optic  nerve  forward  to  the 
margin  of  the  pupil. 

The  retina  is  usually  described  as  consisting  of  eight  layers  and 
two  limitinii;  membranes ;    of  these  layers,  three  are  most  impor- 
tant :  — 

(1)  Eighth  layer,  or  layer 
of  nerve-fibres,  is  the  internal 
layer. 

(2)  Seventh  layer  is  the 
layer  of  nerve-cells. 

(3)  First  layer,  or  layer  of 
rods  and  cones,  is  the  external 
layer.  (See  Summary,  page 
440.) 

The  fibres  of  the  optic 
nerve,  after  piercing  the  sclera 
and  choroid  at  the  back  of 
the  eye,  spread  out  and  form 
the  eighth,  or  innermost, 
layer  of  the  retina.  The  fibres 
then  pass,  with  more  or  less 
direct  communications,  pe- 
ripherally through  the  other 
layers,  until  they  may  be  said 
to  terminate  in  the  layer  of 
rods  and  cones.  Rays  of  light 
produce  no  efi'ect  upon  the 
optic  nerve  without  the  in- 
tervention of  the  rods  and 
cones,  which  act  as  end 
organs. 
Blind  spot.  —  The  optic 
ner\e  pierces  the  eyeball  not  exactly  at  its  most  posterior  point, 
but  a  little  to  the  iimer  side.  This  point  where  the  optic  nerve 
enters  is  called  the  blind  spot.  There  are  no  rods  and  cones  at  this 
spot,  and  rays  of  light  falling  upon  it  produce  no  sensation. 

Macula  lutea.  —  There  is  one  point  of  the  retina  that  is  of  great 
importance,  and  that  is  the  macula  lutea,  or  yellow  spot.  It  is 
situated  about  one-twelfth  inch  (2.08  mm.)  to  the  outer  side  of  the 


Fio.  201.  —  Diagrammatic  bEcrioN  of 
THE  Human  Retina.  8,  layer  of  nerve- 
fibreo;  7,  layer  of  nerve-cells;  1,  layer  of 
rods  and  cones.     (M.  Schultze.) 


Chap.  XX]     INTERNAL  AND   EXTERNAL  SENSES       129 


exit  of  the  optic  nerve,  and  is  the  exact  centre  of  the  retina.  Li 
its  centre  is  a  tiny  pit,  —  fovea  centralis,  —  which  is  the  centre 
of  direct  vision ;  that  is,  it  is  the  part  of  the  retina  which  is  always 
turned  towards  the  object  looked  at.  From  this  point  the  sensi- 
tiveness of  the  retina  grows  less  and  less  in  all  directions.  At 
this  point  (fovea  centralis)  are 
found  none  of  the  fibres  of  the 
optic  nerve,  but  a  great  increase 
in  the  number  of  cones,  as  well 
as  in  their  size. 

Perception  of  light.  —  'Wlien 
light  waves  fall  upon  the  retina 
they  act  as  a  stimulus,  and  it  is 
supposed  that  they  cause  chem- 
ical changes  in  the  rods  and 
cones  which  give  rise  to  im- 
pulses that  are  carried  by  the 
optic  nerve  to  the  brain,  and 
result  in  sight.  Just  how  this 
is  accomplished  is  not  known, 
but  the  rods  contain  a  kind  of 
pigment  which  is  called  visual 
purple,  and  this  as  well  as  the 
pigment  of  the  retina  may  func- 
tion in  these  changes. 

The  optic  chiasm.  —  The  fact  that  the  two  retinse  and  the  two 
eyeballs  work  in  unison  is  largely  due  to  the  crossing  of  the  nerve 
fibres  at  the  optic  chiasm.  The  optic  nerve  from  each  eye  passes 
backward  through  the  optic  foramen,  and  shortly  after  leaving 
the  orbit  the  two  nerves  come  together,  and  the  fibres  from  the 
inner  portion  of  each  nerve  cross.  This  is  called  the  optic  chiasm, 
and  is  really  an  incomplete  crossing  of  fibres,  as  the  outer  fibres 
do  not  cross.     (See  Fig.  203.) 

Aqueous  humor.  —  The  space  bounded  by  the  cornea  in 
front  and  by  the  lens,  suspensory  ligament,  and  ciliary  body  be- 
hind is  filled  with  a  colorless,  transparent,  watery  fluid,  the 
aqueous  humor.  This  space  is  known  as  the  aqueous  chamber, 
and  is'  partially  divided  by  the  iris  into  an  anterior  and  posterior 
chamber. 


Fig.  202.  —  The  Posterior  Half  of 
THE  Retina  of  the  Left  Eye  viewed 
FROM  Before.  Twice  its  natural  size, 
s,  cut  edge  of  the  sclera  ;  ch,  choroid  ;  r, 
retina  ;  in  the  interior  at  the  middle,  the 
macula  lutea  with  the  depression  of  the 
fovea  centralis  is  represented  by  a  slight 
oval  shade  ;  toward  the  left  side  the  light 
spot  indicates  the  entrance  of  the  optic 
nerve  or  blind  spot.      (Collins.) 


430  ANATOMY   FOR   NURSES  [Chap.  XX 

Vitreous  humor.  —  The  posterior  four-fifths  of  the  globe  of  the 
eyeball  is  filled  with  a  semi-fluid,  gelatinous  substance,  the  vit- 
reous humor,  or  body,  so  called  from  its  glassy  and  transparent 
appearance.     It  is  enclosed  in  a  thin  membrane  —  the  hyaloid 

membrane.       This     mem- 

^1  A  brane  is     attached  to    the 

^>~^r  )jf^     retina  at  the    back  of  the 

\  ^^  /^  eyeball,  and  furnishes  a  sus- 

p  ic  nerM  \^k.    /jW  peusory  ligament  to  the  lens. 

Optic  chiasm. — ■ \  ^^f^  Elscwhcre    it    is    perfectly 

/    y^^^^^^  separable  from  its  surround- 

optic  tract ^y/  ^%^  "^Ss-     The  vitreous  humor 

enclosed  in  this  capsule  dis- 

FiG.  203.  —  DiAGR.wi  OF  Optic  Chiasm. 

tends  the  greater  part  oi 
the  sclera,  supports  the  retina,  which  lies  upon  its  surface,  and 
preserves  the  spheroidal  shape  of  the  eyeball.  Its  refractive 
power,  though  slightly  greater  than  that  of  the  aqueous  humor, 
does  not  differ  much  from  that  of  water. 

Crystalline  lens.  —  The  crystalline  lens  is  a  transparent,  refrac- 
tive body,  with  convex  anterior  and  posterior  surfaces,  placed 
directly  behind  the  pupil,  where  it  is  retained  in  position  by  the 
counterbalancing  pressure  of  the  aqueous  humor  and  vitreous 
body,  and  by  its  own  suspensory  ligament  described  above. 
The  posterior  surface  is  considerably  more  curved  than  the  an- 
terior, and  the  curvature  of  each  varies  with  the  period  of  life. 
In  infancy,  the  lens  is  almost  spherical ;  in  the  adult,  of  medium 
convexity  ;   and  in  the  aged,  considerably  flattened. 

It  is  a  fibrous  body,  enclosed  in  an  elastic,  non-vascular  capsule. 
Just  beneath  the  capsule  the  substance  is  soft  and  gelatinous, 
but  deeper  it  becomes  hard  and  firm.  Its  refractive  power  is 
much  greater  than  that  of  the  aqueous  or  vitreous  humor. 

Refraction.  —  Refraction  is  the  bending  or  deviation  in  the 
course  of  rays  of  light  in  passing  obliquely  from  one  transparent 
medium  into  another  of  difl'erent  density.     (See  page  496.) 

The  refractive  apparatus.  —  In  order  that  our  vision  of  objects 
looked  at  should  be  clear  and  distinct  it  is  necessary  that  the  rays 
of  light  entering  the  eye  should  be  focussed  on  the  retina.  In  the 
normal  eye  this  is  secured  by  the  mechanism  of  accommodation 
(see  next  paragraph).     The  refractive  apparatus  consists  of  the 


Chap.  XX]     INTERNAL  AND   EXTERNAL  SENSES       431 

aqueous  humor,  the  vitreous  humor,  and  the  crystalHne  lens  which 
have  just  been  described. 

Accommodation.  —  Accommodation  is  the  ability  of  the  eye 
to  adjust  itself  so  that  it  can  see  objects  at  varying  distances.  Tlie 
changes  which  occur  in  the  eye  during  accommodation  for  near 
objects  are  three  in  number :  (1)  the  pupil  contracts,  (2)  the 
lens  becomes  more  convex,  and  (3)  the  axes  of  the  eyeballs  are 
turned  inward  by  the  action  of  the  internal  recti  muscles. 

A  normal  eye  is  capable  of  distinct  vision  throughout  an  im- 
mense range.  We  can  see  the  stars  millions  of  miles  away,  and 
with  the  same  eye,  though  not  at  the  same  time,  we  can  see  ob- 
jects within  a  few  inches  of  us.  To  be  able  to  see  objects  mill- 
ions of  miles  away  and  within  a  short  range,  the  eye  has  to 
accommodate  or  adjust  itself  to  different  distances.  This  accom- 
modation is  accomplished  mainly  by  the  lens  changing  its  con- 
vexity. In  accommodation  for  near  objects,  the  lens  becomes 
more  convex  (advances),  and  the  pupil  of  the  eye  hkewise  con- 
tracts. This  convexity  is  brought  about  by  the  action  of  the 
ciliary  muscle,  and  is  always  more  or  less  fatiguing.  The  ac- 
commodation for  distant  objects  is  a  passive  condition,  the 
convexity  of  the  lens  being  unaltered  and  the  pupil  of  the  eye 
dilated,  and  it  is  on  this  account  that  the  eye  rests  for  an  indefi- 
nite time  upon  remote  objects  without  fatigue. 

Common  conditions  that  affect  accommodation.  —  The  condi- 
tions that  affect  accommodation  are  :  (1)  hypermetropia,  (2)  myo- 
pia, (3)  presbyopia,  and  (4)  astigmatism. 

H3rpermetropia.  —  Hypermetropia  or  far-sightedness  is  a  condi- 
tion in  which  rays  of  light  from  near  objects  do  not  converge  soon 
enough  and  are  brought  to  a  focus  behind  the  retina.  This  is  usu- 
ally caused  by  a  flattened  condition  of  the  lens  or  cornea,  or  an 
eyeball  that  is  too  shallow,  and  convex  glasses  are  used  to  con- 
centrate and  focus  the  rays  more  quickly. 

Myopia.  —  Myopia  or  near-sightedness  is  a  condition  in  which 
rays  of  light  converge  too  soon,  and  are  brought  to  a  focus  before 
reaching  the  retina.  This  is  the  opposite  of  hj-permetropia  and 
is  caused  by  a  cornea  or  lens  that  is  too  convex,  or  an  eyeball  of 
too  great  depth.  To  remedy  this  condition  concave  glasses  are 
worn  to  disperse  the  rays  and  prevent  their  being  focussed  too 
soon. 


432 


ANATOMY  FOR   NURSES 


[Chap.  XX 


Presbyopia.  —  Presbyopia  is  a  defective   condition  of   accom- 
modation   in    which    distant    objects    are   seen    distinctly,    but 

near  objects  are  indistinct.  This 
is  a  physiological  process  which 
affects  every  eye  sooner  or  later, 
and  is  not  due  to  disease.  It  is 
said  to  be  caused  by  a  loss  of 
elasticity  of  the  l^ns. 

Astigmatism.  —  Astigmatism 
is  the  condition  in  which  the 
different  meridians  ^  of  the  cor- 
nea are  not  equally  convex,  and 
so  there  is  interference  with 
the  formation  of  distinct  images 
on  the  retina. 

Inversion  of  images.  —  Fol- 
lowing the  general  laws  for  the 
formation  of  images  in  connec- 
tion with  the  lens,  an  inverted 
image  of  external  objects  is 
formed  on  the  retina. 
"  The  question  then  arises,  WTiy  is  it  that  objects  do  not  appear 
to  us  to  be  upside  down  ?  This  cannot  be  satisfactorily  answered 
without  entering  into  matters  which  require  a  previous  psychologi- 
cal training.  Suffice  it  to  say  here  that  the  localization  of  objects 
in  space  depends  not  only  on  the  retina,  but  also  on  tactile  and 
general  experience ;  that  the  mind  localizes  objects  with  reference 
to  its  own  body,  and  that  from  the  first  it  knows  nothing  of  the  in- 
version of  the  retinal  image,  as  its  powers  of  localization  only  ap- 
pear with  developing  general  experience."     (Halliburton.) 

•  The  meridian  of  the  eye  is  an  imaginary  line  drawn  around  the  eyeball. 


Fig.  204.  —  Diagram  illustrating 
Ray.s  of  Light  converging  in  (A)  a 
Normal  Eye,  (B)  a  Myopic  Eye,  and 
(C)  A  Hyper.metropic  Eye. 


Chap.  XX] 


SUMMARY 


433 


SUMMARY 

'  Perception  through  the  sense  organs. 


Sensation 


Organs 
necessary 
for    sensa- 
tion 


Classification  < 


End  organ  for  the  reception  of  a  stimulus. 
A  nerve  for  conduction  of  the  stimulus. 
A  centre  in  the  brain  for  the  perception  and 
interpretation. 

1.  Internal  or  those  in 

which  the  sensa- 
tions are  pro- 
jected to  the  in- 
terior of  the 
body. 

2.  External  or  those  in 

which  the  sensa- 
tions are  pro- 
jected to  the  ex- 
terior of  the 
body. 


Hunger. 

Thirst. 

Pain. 

Muscular  sense. 

Fatigue. 

Visceral  sensations . 

Pressure. 

Temperature. 

Taste. 

Smell. 

Hearing. 

Sight. 


Hunger 


Thirst 


Pain 


Presumably  due  to  contractions  of  empty  stomach,  act- 
ing on  nerves  distributed  to  mucous  membrane. 

In  abnormal  conditions  it  may  be  due  to  failure  to  assimi- 
late food. 

/  Presumably  due  to  stimulation  of  nerves  of  pharynx  by 
1      low  water  content  in  tissues. 

f  May  be  due  to  stimulation  of  special  nerve  endings,  or  to 

I      overstimulation  of  any  of  the  sensory  nerves. 
Muscular  Sense  —  Due  to  stimulation  of  sensory  nerves  distributed  to 

muscles.     Weight  or  resistance  serves  as  stimulus. 
Fatigue  —  Due  to  stimulation  of  sensory  nerves  distributed  to  muscles. 

Loss  of  nutrient  material  or  accumulation  of  waste  products 

acts  as  stimulus. 
Visceral  Sensations  —  Due  to  stimulation  of  sensory  nei-ves  distributed 
to  the  \'iscera. 

r  End  organs  distributed  over  entire  surface  of  body. 
Pressure     •   |  -^  j  /  Nerve  filaments  surround  hair  foUicles. 

i  1  Tactile  or  Meissner  corpuscles. 

End  organs  distributed  over  entire  surface  of  body. 

r  Temperature  higher  than  body. 
Hot  spots  I  Carbon  dioxide. 
Temperature  {  ^^^  organs     J  Electricity. 

^  (  Temperature  lower  than  body. 

Cold  spots  I  Menthol. 
I  Electricity. 
2f 


434 


ANATOMY  FOR  NURSES 


[Chap.  XX 


Taste 


Tongue 


1.  Taste-buds  are  end  organs. 
Sensory    &p-    2.  Nerve-fibres  of  trifacial,  facial,  and  glos- 
paratus        |  sopharyngeal  nerves. 

.  3.  Centre  in  brain. 
Solution  of  sapid  substances  must  come  in  contact  with 
taste-buds. 

(Surface  of  tongue. 
Soft  palate  and  fauces. 
Tonsils  and  pharynx. 

Freely  movable  muscular  organ. 

Attached  to  hyoid  bone,  epiglottis,  and  pillars  of  the  fauces. 

ICircumvallate. 
Fungiform. 
Filiform. 
■  Lingual,  branch  of  trifacial. 


Nerves 


Sense  of 


Sensory 


Motor  — 

1.  Taste 

2.  Temperature 

3.  Pressure 

4.  Pain 


Chorda  tympani,  branch  of  the 

facial. 
Glossopharyngeal. 
Hypoglossal. 


Are  all  well  developed. 


Smell 


Hearing 


C  Olfactory  nerve-endings. 
Sensory    ap-    olfactory  nerve-fibres. 

para  us        |^  Centre  in  brain  —  olfactory  bulb. 

I  Minute    particles    of  ( Must    be    capable 
solid  matter  <      of    solution     in 

Gases  I      mucus. 

Olfactory  nerve-ending  found  in  lining  upper  part  of  nose 

(smell). 
Branches  of  trigeminal  nerve  found  in  lining  of  lower  part 
of  nose  (pressure). 

'  External  ear. 
Middle  ear. 
Auditory  ap-  <  Internal  ear. 
paratus  Auditory  nerve. 

.  Centre  in  brain. 
Air-waves  enter  external  auditory  canal  and  cause  vibra- 
tions of  drum-nicmbrane.     The  \4brations  are  conveyed 
to  nerve-endings  of  organ  of  Corti,  and  thence  by  the 
auditory  nerve  to  the  brain. 


Chap.  XXJ 


SUMMARY 


435 


Ear    . 


Pinna, 
auricle 


or 


External  Ear. 


Structure 


Fxmction 


Middle  Ear     - 


Cartilaginous 
framework, 
some  fatty 
and  muscular 
tissue,  cov- 
ered with 
skin. 

Collects  sound- 
waves and  re- 
flects them 
into  the  audi- 
tory canal. 
'  1  in.  long,  partly  cartilage, 

partly  bone. 
Closed  inter- 
nally      by 
the    drum- 
membrane 
Hairs  directed  outward. 
Ceruminous  glands  secrete 
a  yellow,  pasty  substance. 
An  irregular  cavity  in  the  temporal  bone. 
Five  or  six  drops  of  water  will  fill  it. 
r  Malleus  (hammer). 
<  Incus  (anvil). 
I  Stapes  (stirrup). 
■  Fenestra  ovalis  —  closed  by 
a    membrane    and    the 
stapes. 
Fenestra  rotunda  —  closed 

by  a  membrane. 
Eustachian      tube  —  con- 
nects with  the  pharynx, 
allows  entrance  of  air. 


Auditory 
canal 


Membrana 

tympani. 


Bones 


Openings 


436 


ANATOISIY  FOR  NURSES 


[Chap.  XX 


Internal  ear 


Ear 


Vestibule  —  antechamber 
just  inside  of  fenestra 
oralis . 


Semicir- 
cular 
canals 


Cochlea 


Auditory 
nerve 


Three  in  num- 
ber. 

Open  into  ves- 
tibule. 
Vestibular  branch  of  audi- 
Bony  tory  nerve  tlistributed  to 

labyrinth     I      vestibule  and  semicircu- 
lar canals. 

A  spiral  tube. 
2^  turns  around 

modiolus. 
Fenestra     ro- 
tunda. 
Cochlear  branch 
of  the   audi- 
tory nerve. 
'  Surrounded  by  perilymph. 
Contains  endoljTiiph. 
Lines  the  vesti-  f  Saccule, 
bule  \  Utricule. 

Lines      the      semicircular 

canals. 
Lines  the  cochlea,  and  here 
Membranous  i      it   is   called   the   canalis 
labyrinth  cochlearis,  or  scala  media. 

Menibrana  basilaris  is  name 
given  to  membrane  at 
base  of  canal. 
Organ  of  Corti,  name  given 
to  end  organs  of  auditory 
nerve  lodged  on  mem- 
brana  basilaris. 
Cochlear  —  terminates  in  and  around  cells 

of  organ  of  Corti. 
Vestibular  —  terminate    in    hair-cells    of 
saccule,  utricle,  and  ampulla. 


Chap.  XX] 


SUMMARY 


437 


Sense  of 
Equilibrium 


Sight 


Ascessory 
Organs 


Function  of  the  vestibule  and  semicircular  canals. 

Lining  membrane  supplied  with  sensory  hairs  which  con- 
nect with  vestibular  nerve. 

Contain  several  small  otoliths  which  float  intheendoljanph. 

Flowing  of  the  endolyraph  stimulates  the  sensory  hairs; 
this  is  transmitted  to  the  vestibular  nerve,  thence  to 
auditory  nerve,  thence  to  brain. 

'  Eye. 

Optic  nerve. 
Centre  in  brain. 

Eyebrows. 
Accessory  Eyelids. 

organs         ]  Lacrimal  apparatus. 
Muscles. 

Vibrations  in  the  ether  enter  eye  and  strike  on  retina, 
which  contains  end  organs  of  the  optic  nerve;  thence 
sensation  is  carried  to  visual  centre  in  brain. 


Visual  ap- 
paratus 


Eyebrows 


Eyelids 


Arched  eminences  of  skin  furnished  with 
short,  thick  hairs. 

Control  to  a  limited  extent  amount  of  light 
admitted  to  eye. 

'  Folds  of  connective  tissue  covered  with 
skin,  lined  with  mucous  membrane  (con- 
junctiva), which  is  also  reflected  over 
the  eyeball.     Provided  with  lashes. 

Closed  by  orbicularis  palpebrarum  muscle. 

Upper  lid  raised  by  levator  palpebrae  su- 
perioris. 

Slit  between  lids  called  palpebral  fissure. 

Inner  angle  of  slit  called  internal  canthus. 

Outer  angle  of  slit  called  external  canthus. 

Function  is  protection.     Serve  as  shades. 

Tarsal  glands  are  a  row  of  glands  embedded 
in  tarsal  cartilage  of  each  lid. 


438 


ANATOMY  FOR   NURSES 


[Chap.  XX 


Accessory 
Organs 


Nerves  of 
Eye 


Lacrimal 
apparatus 


Tears 


Consist 
of 


Lacrimal  gland  —  in  the  upper  and  outer 

part  of  tlie  orbit.     Secretes  tears. 
Ducts  —  7  to  12  lead  from  gland  to  con- 
junctiva. 
Canaliculi  —  2  canals  y  to  ^  in.  long,  begin 

at  punctae  and  open  into  lacrimal  sac. 
Lacrimal  sac  —  upper  dilated  portion  of 

the  nasal  duct. 
Xasal  duct  —  canal  f  in.  long,  extends  from 
lacrimal  sac  to  the  nose. 

Secretion  constant. 
Moisten    the    eyeball  and 
help  to  moisten  inspired 
air. 

f  Water. 
{  Salt. 
I  Albumin. 
Carried  off  by  nasal  duct. 
'  Superior  rectus. 
Inferior  rectus. 
Internal  rectus. 
External  rectus. 
Superior  obUque. 
,  Inferior  obUque. 

Determines    the 
position  of  the 
I      lens, 
r  Contractor     of 

pupil. 
I  Dilator  of  pupil. 
■  1.  Optic  nerve  concerned  with  vision  only. 
Internal  rectus  muscle. 
Superior  rectus  muscle. 
Inferior  rectus  muscle. 
Inferior  obUque  muscle. 

3.  Pathetic  controls  the  superior  obUque  muscle. 

4.  Abducens  controls  the  external  rectus  muscle, 
l  5.  Ophthalmic. 


Muscles 


Extrinsic 


Intrinsic 


Ciliary 
muscle 

Muscles 
of  iris 


2.  Motor 
oculi 
controls 


Chap.  XX] 


SUMMARY 


439 


Orbit 


Eyeball 


Bony  cavity  formed  by  seven  bones 


Frontal. 

Malar. 

Maxilla. 

Palate. 

Ethmoid. 

Sphenoid. 

Lacrimal. 


Lined  by  fibrous  tissue. 

Contains  pad  of  fat  —  supports  eyeball. 

Capsule  of  Tenon  —  prevents  friction  when  eyeball  moves. 

Shaped  Uke  four-sided  pyra-  J  Apex  directed  backward. 

mid  \  Base  directed  forward. 

Optic  foramen  —  opening  for  passage  of  optic  nerve  and 

ophthalmic  artery. 
Sphenoidal  fissure  —  opening  for  passage  of  ophthalmic 
vein  and  motor  oculi,  pathetic  and  abducens  nerves. 
■  Spherical  in  shape. 

Transverse  .     .     .     1.00  inch  (25  mm.) 

Vertical 96  inch  (24  mm.) 

Antero-posterior   .       .96  inch  (24  mm.) 
Optic    nerve    and 

Dimensions    I      sheath 16  inch  (4  mm.) 

Lens  — ^  antero-pos- 
terior   19  inch  (4.75  mm.) 

Lens  —  transverse       .35  inch  (8.75  mm.) 
Pupil  (average)     .       .14  inch  (3.5  mm.) 


Tunics 


Media 


1.  Sclera  and  cornea. 

2.  Choroid,  ciliary  body,  and  iris. 

3.  Retina. 

1.  Aqueous. 

2.  Crystalline  lens  and  capsule. 

3.  Vitreous. 


Sclera 


Cornea 


Choriod 


Ciliary  Body 


(  Tough,  fibrous,  opaque.     Protective. 
I  Covers  posterior  |  of  eyeball. 
I  Stained  brown  internally. 
Fibrous,  transparent  —  covers  anterior  I  of  eyeball. 
Well  supplied  with  nerves, 
r  Vascular  coat,  lines  the  sclera. 

I  Composed  of  connective  tissue  cells  filled  with  pigment. 
i  Terminates  in  front  by  the  ciliary  processes. 
Ciliary  processes  70  to  80  parallel  folds  of  the  choroid, 
rising  gradually  from  behind  and  forming  a  plaited  zone 
between  the  choroid  and  iris. 
Support  ciliary  muscle  —  action  of  this  muscle  determines 
the  position  of  the  lens. 


440 


ANATOMY   FOR  NURSES 


[Chap.  XX 


Iris 


Retina 


Refractive 
Apparatus 


A  circular  curtain.     Central  perforation  —  pupil. 

Pupil  contracted  by  circular  muscle-fibres. 

Pupil  dilated  by  radial  muscle-fibres. 

Contains  pigment  —  amount  gf  which  determines  color  of 

the  eyes. 
Hangs  free  except  for  attachment  at  circumference  to  the 

ciliar}'  processes  and  choroid. 
Function  —  Regulates  amount  of  light  entering  eye. 

Visual  layer  —  transparent  membrane  of  nervous  and  con- 
nective tissue  situated  between  the  choroid  and  vitreous 
humor.     Formed  by  the  spreading  out  of  optic  nerv'c. 

Has  eight  layers  and  two  membranes.  Counting  from  the 
choroid  inward  as  follows  :  — 

Pigment  layer,  usually  described  as  a  membrane. 

1.  Layer  of  rods  and  cones  (perceptive  layer)  — external 

layer. 

2.  Limitans  externa, 

3.  External  granules. 

4.  External  molecular. 

5.  Internal  granules. 

6.  Internal  molecular. 

7.  GangUon  or  nerve-cells. 

8.  Optic  nerve-fibres  —  innermost  layer. 
Membrana  Umitans  interna. 

(  Entrance  of  optic  nerve. 

<  There  are  no  rods  and  cones. 

[  Totally  insensitive  to  light. 

1^  in.  outside  the  blind  spot. 

Central  pit  —  fovea  centralis  —  is  the  centre  of 
direct  vision. 


Blind 
spot 

Macula 
lutea 


Aqueous 


Vitreous 


Crystal- 
line 
lens 


Aqueous  chamber  is  between  cornea  in  front  and 
lens,  suspensorj'  ligament,  and  ciliarj'  body 
behind.     Aqueous  humor  is  a  colorless,  trans- 
parent, watery  fluid. 
■  Semi-fluid,  gelatinous  substance. 

Fills  the  posterior  four-fifths  of  the  globe  of  the 
eyeball,  and  is  enclosed  in  the  hyaloid  mem- 
brane. Distends  the  sclera  and  supports  the 
retina. 

Situated  behind  the  pupil.  Double  convex  in 
shape. 

Fibrous  body  enclosed  in  an  elastic  capsule. 

Held  in  position  by  counterbalancing  of  the 
aqueous  and  vitreous  humor  and  the  sus- 
pensory ligament. 


Chap.  XX] 


SUMMARY 


441 


Refraction  —  Bending  or  deviation  in  the  course  of  rays  of  light,  in  pass- 
ing obUquely  from  one  transparent  medium  into  another  of 
different  density. 

Accommodation  —  AbiUty  o£  the  eye  to  adjust  itself  so  that  it  can  see 
objects  at  varying  distances. 


Conditions 
that  affect 
Accommo- 
dation 


Hypermetropia 


Myopia 


Presbyopia 


Astigmatism 


Far-sightedness. 

Cause  —  Rays  of  hght  do  not  con- 
verge soon  enough. 

Xear-sightedness. 

Cause  —  Rays  of  light  converge  too 
soon. 

Defective  condition  of  accommodation 
in  which  distant  objects  are  seen 
distinctly,  but  near  objects  are  in- 
distinct. 

Condition  in  which  the  different  merid- 
ians of  the  eye  are  not  equally 
convex.     Interferes    with    distinct 


CHAPTER   XXI 

THE   ORGANS   OF   GENERATION  :    PHYSIOLOGY   OF 
REPRODUCTION 

Female  generative  organs.  —  The  female  generative  organs 
are  divided  into  an  internal  and  an  external  group.  The  internal 
are  contained  within  the  pelvis,  and  the  external  are  grouped  under 
the  name  of  vulva  or  pudendum. 

INTERNAL  GENERATIVE  ORGANS 

The  internal  generative  organs  comprise  the  following  struc- 
tures :  — 

(1)  Ovaries,  two  glandular  organs  in  which  the  ova  are  formed. 

(2)  Fallopian  [uterine]  tubes,  two  canals  through  which  the 
ova  reach  the  uterine  cavity. 

(3)  Uterus,  a  hollow,  pear-shaped  organ,  which  receives  the 
ovum. 

(4)  Vagina,  a  canal  extending  from  the  uterus  to  the  vulva. 
Ovaries.  — The  ovaries  are  two  small,  almond-shaped  glandular 

bodies,  situated  one  on  each  side  of  the  uterus,  in  the  posterior  fold 
of  the  broad  ligament,  behind  and  below  the  Fallopian  tubes.  Each 
ovary  is  attached  by  its  inner  end  to  the  uterus  by  a  short  liga- 
ment, —  the  ligament  of  the  ovary,  —  and  by  its  outer  end  to  the 
Fallopian  tube  by  one  of  the  fringe-like  processes  of  the  fimbriated 
extremity.  The  ovaries  each  measure  about  one  and  a  half 
inches  (38  mm.)  in  length,  three-fourths  of  an  inch  (19  mm.) 
in  width,  and  one-third  of  an  inch  (8.5  mm.)  in  thickness,  and  weigh 
from  one  to  two  drachms  (3.7  to  7.5  grams). 

Function.  —  The  function  of  the  ovaries  is  to  produce,  develop, 
and  mature  the  ova,  and  to  discharge  them  when  fully  formed. 
In  addition,  the  ovary  doubtless  furnishes  an  internal  secretion, 
which  is  picked  up  by  the  blood. 

Structure.  —  If  the  substance  of  an  ovary  be  minutely  examined 
it  is  found  to  consist  of:   (1)  a  stroma  or  bed  composed  of  white 

442 


Chap.  XXI]    THE  ORGANS  OF  GENERATION 


443 


and  yellow  fibrous  tissue,  blood-vessels,  lymphatics,  and  nerves, 
(2)  Graafian  or  vesicular  follicles,  and  (3)  a  covering  of  columnar 
epithelial  cells,  called  germinal  epithelium,  which  is  continuous 
with  the  peritoneum. 

Graafian  (vesicular)  follicles.  —  The  Graafian  follicles  are  sacs 
or  vesicles  which  contain  the  ova  and  are  embedded  in  the  meshes 
of  the  stroma. 

Each  follicle  consists  of :  (1)  an  outer  coat  of  fibrous  tissue  that 
is  derived  from  the  stroma,  and  connected  with  it  by  a  plexus  of 


Fig.  205.  —  Uterus,  Fallopian  Tubes,  and  Ovaries  —  Posterior  View. 
1,  ovaries;  2,  2,  uterine  tubes;  3,  3,  fimbriated  extremity  of  the  left  uterine 
tube,  seen  from  its  concavity ;  4,  opening  of  the  left  tube  ;  5,  fimbriated  extremity 
of  the  right  tube,  posterior  view ;  6,  6,  fimbrise  which  attach  the  extremity  of  each 
tube  to  the  ovary ;  7,  7,  ligaments  of  the  ovary ;  8,  8,  9,  9,  broad  ligaments ;  10, 
uterus;    11,  cervix  uteri ;    12,  os  uteri ;    13,  13,  14,  vagina.     (Sappey.) 

blood-vessels,  and  (2)  an  inner  layer  of  nucleated  cells.  With 
the  exception  of  the, smallest  vesicles  each  one  is  filled  with  fluid, 
and  suspended  in  this  fluid  is  an  ovum  surrounded  by  a  mass  of 
cells,  called  the  discus  proligerus. 

At  birth  the  ovaries  are  said  to  contain  about  36,000  vesicles, 
each  measuring  from  gro  to  j^  of  an  inch  in  diameter,  but  only  a 
small  number  of  these  ever  develop,  as  the  great  majority  shrink 
and  disappear.  At  the  time  of  puberty  the  ovaries  enlarge,  be- 
come very  vascular,  and  some  of  the  follicles  increase  in  size.  As 
the  follicles  increase  in  size  they  approach  the  surface  and  begin 
to  form  small  protuberances  on  the  outside  of  the  ovary.     When 


444  ANATOMY  FOR  NURSES  [Chap.  XXI 

fully  matured  the  wall  of  the  ovary  and  the  wall  of  the  follicle  burst 
at  the  same  point,  and  the  contents  of  the  follicle  —  the  fluid, 
the  ovum,  and  the  surrounding  cells  —  escape.  This  process  of 
development,  maturation,  and  rupture  of  a  follicle  is  kncnvn  as 
ovulation,  and  continues  at  regular  intervals  from  puberty  to  the 
menopause. 

The  corpus  luteum.  —  After  the  rupture  of  a  follicle,  and  the 
escape  of  the  ovum,  the  walls  collapse  and  the  cavity  becomes 
filled  with  blood  which  forms  a  clot.  Later  this  clot  becomes 
surrounded  by  cells  containing  a  yellow  pigment,  which  gives  the 
follicle  a  yellow  color,  and  hence  it  is  known  as  the  corpus  luteum. 
The  size  and  duration  of  the  corpus  luteum  is  dependent  on  whether 
fertilization  occurs  or  not.  If  fertilization  does  not  occur  the  cor- 
pus luteum  increases  in  size  for  two  or  three  weeks  and  then  is  ab- 
sorbed. If  fertilization  does  occur  and  the  woman  becomes  preg- 
nant, the  corpus  luteum  increases  in  size  during  the  first  few 
months,  and  does  not  show  retrogressive  changes  until  about  the 
sixth  month.  The  function  of  the  corpus  luteum  is  unknown. 
Some  physiologists  regard  it  as  a  protective  mechanism  by  means  of 
which  the  cavity  resulting  from  the  rupture  of  the  follicle  is  filled 
with  a  tissue  which  can  be  easily  absorbed.  Others  attribute  to 
the  corpus  luteum  the  formation  of  the  internal  secretion  of  the 
ovaries.     This  will  be  discussed  later. 

Fallopian  tubes.  —  The  Fallopian  tubes  or  oviducts  are  two  in 
number,  one  on  each  side,  and  pass  from  the  upper  angles  of  the 
uterus  in  a  somewhat  tortuous  course  between  the  folds  and  along 
the  upper  margin  of  the  l)road  ligament,  towards  the  sides  of  the  pel- 
vis. They  are  about  four  inches  (100  mm.)  long,  and  at  the  point 
of  attachment  to  the  uterus  are  very  narrow,  but  gradually  increase 
in  size  so  that  the  distal  end  is  larger.  The  margin  of  the  distal 
end  is  surrounded  by  a  number  of  fringe-like  processes  called  fim- 
briae. .  One  of  these  fimbrise  is  attached  to  the  ovary.  The  uterine 
opening  of  the  tube  is  minute,  and  will  only  admit  a  fine  bristle ; 
the  abdominal  opening  is  comparatively  much  larger. 

The  uterine  tube  consists  of  three  coats  :  — 

(1)  Serous.  —  The  external,  or  serous,  coat  is  derived  from  the 
peritoneum. 

(2)  Muscular.  —  The  middle,  or  muscular,  coat  has  two  layers  : 
one  a  layer  of  longitudinal  fibres  and  the  other  of  circular  fibres. 


Chap.  XXI]     THE   ORGANS   OF  GENERATION  445 

(3)  Mucous.  —  The  internal,  or  mucous,  coat  is  arranged  in 
longitudinal  folds  and  covered  with  ciliated  epithelium.  It  is  con- 
tinuous at  the  inner  end  with  the  mucous  lining  of  the  uterus,  and 
at  the  distal  end  with  the  serous  lining  of  the  abdominal  cavity. 
This  is  the  only  instance  in  the  body  in  which  a  mucous  and  serous 
lining  are  continuous  with  one  another. 

Function.  —  The  function  of  the  Fallopian  tubes  is  to  convey 
the  ova  from  the  ovaries  to  the  uterus.  Just  how  the  ovum, 
after  its  discharge  into  the  abdominal  cavity,  reaches  the  Fallopian 
tube  is  not  known.  It  is  thought  that  the  movement  of  the  cilia 
on  the  fimbriae  and  in  the  tubes  produces  a  current  which  draws  the 
ovum  into  the  tube.  After  the  ovum  enters  the  tube  it  is  carried 
to  the  uterus  by  the  peristaltic  action  of  the  tube  and  the  move- 
ment of  the  cilia.  It  is  considered  probable  that  many  of  the  ova 
discharged  from  the  ovaries  remain  in  the  abdominal  cavity, 
because  of  failure  to  reach  the  tubes.  These  ova  disintegrate,  are 
absorbed,  and  carried  away  by  the  blood.  Occasionally  such  an 
ovum  becomes  impregnated  and  ectopic  gestation  results. 

The  Uterus.  —  The  uterus  is  a  hollow,  pear-shaped  organ.  In 
the  virgin  state  it  is  situated  in  the  pelvic  cavity  between  the  blad- 
der and  the  rectum.  Its  length  is  estimated  to  be  about  three  inches 
(75  mm.),  its  width  two  inches  (50  mm.),  and  its  thickness  one  inch 
(25  mm.).  During  pregnancy  the  uterus  becomes  enormously  en- 
larged, attains  the  length  of  a  foot  (300  mm.)  or  more,  measures 
about  eight  to  ten  inches  (200  to  250mm.)  transversely,  and  extends 
into  the  umbilical  region.  After  parturition  the  uterus  returns  to 
almost  its  original  size,  but  is  always  larger  than  before  pregnancy. 
After  the  menopause,  the  uterus  becomes  smaller  and  atrophies. 

Divisions.  —  For  purposes  of  description  the  uterus  is  divided 
into  three  parts :    the  fundus,  body,  and  neck. 

The  fundus  is  the  convex  part  above  the  entrance  of  the  tubes. 

The  body  is  the  part  between  the  fundus  and  the  neck. 

The  cervix  or  neck  is  the  lower  constricted  part  and  extends  from 
the  body  of  the  uterus  into  the  vagina. 

The  cavity  of  the  uterus  is  small ;  that  part  within  the  body 
is  triangular  in  shape  (v),  and  has  three  openings,  one  at  each 
upper  angle,  communicating  with  the  Fallopian  tubes,  and  one,  the 
internal  orifice,  opening  into  the  cavity  of  the  cervix  below.  The 
cavitv  of  the  cervix,  which  is,  of  course,  continuous  with  the  cavity 


446  ANATOMY  FOR  NURSES         [Chap.  XXI 

in  the  body,  is  constricted  above,  where  it  opens  into  the  body 
by  means  of  the  internal  orifice  (internal  os),  and  below,  where  it 
opens  into  the  vagina  by  means  of  the  external  orifice  (external  os). 


Fig.  206.  —  Internal  Organs  of  Generation.     Showing  the  uterus  in  its  nor- 
mal position  between  the  bladder  and  the  rectum.     (Cooke.) 

Between  these  two  openings  the  canal  of  the  cervix  is  somewhat 
enlarged. 

Structure.  —  The  walls  of  the  uterus  are  thick  and  consist  of 
three  coats :  — 

(1)  An  external  serous  coat  derived  from  the  peritoneum.  It 
covers  all  of  the  uteru.s,  and  the  posterior  surface  of  the  cervix, 
but  not  the  anterior  surface. 

(2)  A  middle  muscular  coat  which  forms  the  bulk  of  the  uterine 
walls.  It  consists  of  layers  of  plain  muscular  tissue  intermixed 
with  blood-vessels,  l\Tnphatics,  and  nerves.  The  arrangement  of 
the  muscle  fibres  is  very  complex,  as  they  run  circularly,  longi- 
tudinally, spirally,  and  cross  and  interlace  in  every  direction. 

(3)  An  internal  mucous  membrane,  which  is  continuous  with  that 
lining  the  vagina  and  Fallopian  tubes.     It  is  highly  vascular,  pro- 


Chap.  XXI]    THE  ORGANS  OF  GENERATION  447 

vided  with  numerous  mucous  glands,  and  is  covered  with  ciliated 
epithehum. 

Blood  supply  of  uterus.  —  The  uterus  is  abundantly  supplied 
with  blood-vessels.  The  blood  reaches  the  uterus  by  means  of 
the  uterine  arteries  from  the  internal  iliacs,  and  the  ovarian  ar- 
teries from  the  aorta.  Where  the  neck  joins  the  body  of  the  uterus, 
the  arteries  from  both  sides  are  united  by  a  branch  vessel,  called 
the  circumflex  artery.  If  this  branch  is  cut  during  a  surgical  opera- 
tion, or  a  tear  of  the  neck  during  parturition  extends  so  far  as  to 
sever  it,  the  hemorrhage  is  very  profuse.  The  arteries  are  re- 
markable for  their  tortuous  course  and  frequent  anastomoses. 
The  veins  are  of  large  size,  and  correspond  in  their  behavior  to  the 
arteries. 

Position  of  the  uterus.  —  The  uterus  is  not  firmly  attached  or  ad- 
herent to  any  part  of  the  skeleton.  It  is,  as  it  were,  suspended  in 
the  pelvic  cavity,  and  kept  in  position  by  ligaments.  A  full 
bladder  pushes  it  backward;  a  distended  rectum,  forward.  It 
alters  its  position,  by  gravity,  or  with  change  of  posture.  During 
gestation  it  rises  into  the  abdominal  cavity. 

The  fundus  of  the  uterus  is  inclined  forward,  and  the  external 
orifice  is  directed  downward  and  backward.  (See  Fig.  206.) 
Anteversion  is  the  condition  where  the  fundus  turns  too  far  forward. 
Retroversion  is  the  condition  where  the  fundus  inclines  backward. 
A  bend  may  exist  where  the  neck  joins  the  body,  and  if  the  body 
is  bent  forward,  it  is  described  as  anteflexion  ;  if  bent  backward, 
retroflexion. 

Ligaments.  —  The  uterus  is  maintained  in  position  by  five 
ligaments.     Three  are  arranged  in  pairs. 

1.  The  broad,  or  lateral  ligaments,  two  in  number,  are  folds 
of  peritoneum  slung  over  the  front  and  back  of  the  uterus,  and 
extending  laterally  to  the  walls  of  the  pelvis.  They  are  composed 
of  two  opposed,  serous  layers,  and  between  these  layers  are  found 
the  following  structures :  (a)  Fallopian  tubes ;  {h)  the  ovaries 
and  their  ligaments ;  (c)  the  round  ligaments ;  {d)  blood-vessels 
and  lymphatics  ;   (e)  nerves ;  (f)  some  smooth  muscle-fibres. 

The  posterior  fold  covers  the  back  of  the  uterus,  and  extends  far 
enough  below  to  also  cover  the  upper  one-fifth  of  the  back  wall 
of  the  vagina,  when  it  turns  up  and  is  reflected  over  the  anterior 
wall  of  the  rectum.     Thus  the  uterus,  with  and  between  its  two 


448  ANATOMY  FOR  NURSES  [Chap.  XXI 

broad  ligaments,  forms  a  transverse  partition  in  the  pelvic  cavity, 
the  bladder,  vagina,  and  urethra  being  in  the  front  compartment, 
and  the  rectum  in  the  l)ack  compartment. 

The  smooth  muscular  fibres  of  the  broad  ligaments  are  derived 
from  the  superficial  muscular  layer  of  the  uterus.  They  pass 
out  between  the  serous  folds  and  become  attached  to  the  pelvic 
fascia,  and  thus  help  to  sustain  the  uterus. 

2.  The  round  ligaments  are  two  rounded,  fibro-muscular  cords, 
situated  between  the  folds  of  the  broad  ligament.  They  are  about 
four  and  a  half  inches  (113  mm.)  long,  and  take  their  origin  from 
the  upper  angle  of  the  uterus  (on  either  side)  in  front  and  a  little 
below  the  attachment  of  the  Fallopian  tube.  They  extend  forward 
and  outward,  and  finally  end  in  the  tissues  of  the  labia  majora 
and  mons  Veneris.  The  round  ligaments  are  composed  of  muscle- 
fibres,  areolar  tissue,  blood-vessels,  and  nerves. 

3.  The  utero-sacral  ligaments  extend  between  the  cervix  and 
sides  of  the  rectum.  They  ser\'e  to  connect  the  cervix  and  %  agina 
with  the  sacrum,  and  are  partly  serous,  partly  of  smooth  muscular 
fibres. 

4.  Anterior  ligament.  —  Between  the  bladder  and  uterus  the 
peritoneum  forms  a  shallow  pouch  called  the  utero-vesical  pouch. 
This  peritoneum,  which  forms  the  floor  of  the  pouch,  is  described 
as  the  anterior  ligament  of  the  uterus. 

5.  Recto-vaginal.  —  Behind  the  uterus  the  peritoneum  forms 
a  second  and  deeper  pouch  called  the  recto-vaginal,  or  cul-de-sac, 
of  Douglas.  This  peritoneum  is  described  as  the  recto-vaginal 
ligament. 

Function.  —  The  function  of  the  uterus  is  to  receive  the  ovum 
from  the  Fallopian  tubes,  and  if  it  becomes  fertilized  to  retain  it 
during  its  development.  Later  when  the  ovum  has  developed 
into  a  mature  foetus,  it  is  expelletl  from  the  uterus,  chiefly  by  the 
contraction  of  the  uterine  walls. 

The  Vagina. — The  vagina  is  a  musculo-membranous  canal  which 
encircles  the  lower  portion  of  the  cervix,  and  extends  downward 
and  forward  from  the  uterus  to  the  \Tjlva. 

The  posterior  wall  is  about  three  and  a  half  inches  (88  mm.) 
long,  while  the  anterior  wall  is  only  three  inches  (75  mm.).  The 
front,  or  anterior  wall,  is  united  by  connective  tissue  with  the 
posterior  walls  of  the  bladder  and  urethra,  the  partition,  or  septum, 


Chap.  XXI]    THE  ORGANS  OF  GENERATION 


449 


between  the  bladder  and  vagina  being  called  the  vesico- vaginal, 
and  that  between  the  urethra  and  vagina  the  urethro-vaginal, 
septum. 

Structure.  —  The  vagina  is  made  up  of  three  coats  :  an  outer, 
fibrous ;  middle,  muscular ;  and  inner,  mucous,  which  in  the 
ordinary  contracted  state  is  thrown  into  fold,  sits  anterior  and 
posterior  walls  being  in  contact.  The  muscular  coat  increases 
during  pregnancy,  and  the  mucous  coat,  because  of  the  transverse 


PREPUCE    OF. 

CLITORIS 

CLANS    CLI 

TORIOIS 


Fig.   207.  —  Sagittal  Section  of  the  Vagina  and  Neighboring  Parts. 

(Gerrish.) 

folds,  or  rugae,  allow  of  dilatation  of  the  canal  during  labor  and 
birth. 

THE  EXTERNAL  ORGANS 

As  previously  stated  the  external  organs  of  generation  are 
grouped  under  the  name  of  vulva  or  pudendum  and  include  the 
following :  — 

1.  Mons  Veneris  4.  The  Clitoris 

2.  Labia  Majora  5.  The  H^men 


3.  Labia  ^Minora 


G.  Glands 


A'ulvo-vaginal 
Urethral 


Mons  Veneris.  —  The  mons  Veneris  is  an  eminence  situated  in 
front  of  the  pubic  bones.  It  consists  of  areolar,  adipose,  and 
fibrous  tissue  covered  with  skin  and  after  puberty  with  hair. 


2g 


450 


ANATOMY  FOR   NURSES  [Chap.  XXI 


Labia  majora.  —  The  labia  majora  ("  greater  lips  ")  are  two 
longitudinal  folds  of  skin  containing  adipose  and  connective  tissue. 
They  are  continuous  with  the  mons  Veneris  in  front,  and  extend  to 
within  an  inch  (25  mm.)  of  the  anus  behind. 

Labia  minora. — The  labia  minora  ("smaller  lips")  are  two 
longitudinal  folds  of  modified  epithelium  situated  between  the 

MONS    VENERIS 


Fro.  208.  —  Vulva  of  a  Virgin.  The  labia  have  been  widely  separated.  Foss. 
Nav.,  fossa  navicularis ;  Int.  Vag.,  introitus  vaginae ;  Lab.  Miu.,  labium  minus; 
Vestib.,   vestibule.     (Gerrish.) 


labia  majora.  They  are  joined  anteriorly  in  the  hood  or  prepuce 
of  the  clitoris,  and  extend  downward  and  backward  for  about  one 
and  one-half  inches  (38  mm.). 

The  clitoris.  —  The  clitoris  is  a  small  body  situated  at  the  apex 
of  the  triangle  formed  by  the  junction  of  the  labia  minora.  It 
contains  many  vessels  and  nerves  and  is  almost  completely  covered 
by  the  hood  or  prepuce. 


Chap.  XXI]    THE  ORGANS  OF  GENERATION  451 

The  hymen.  —  The  hymen  is  a  fold  of  mucous  membrane  which 
surrounds  the  lower  part  of  the  vaginal  orifice  and  renders  the 
orifice  smaller.  Occasionally  it  extends  entirely  across  and  closes 
the  orifice  altogether.  This  condition  is  spoken  of  as  imperforate 
hymen. 

Glands.  —  In  connection  with  the  vulva  are  found  — 

(1)  Vulvo-vaginal  glands  or  glands  of  Bartholin. 

(2)  Urethral  glands. 

The  vulvo-vaginal  are  two  round,  or  oval,  glands,  situated  on 
either  side  of  the  vagina.  Their  ducts  open  into  the  vulval  canal, 
one  on  either  side,  in  the  groove  between  the  hymen  and  labia 
minora.    Their  secretion  lubricates  the  vulval  canal. 

The  urethral  glands  are  found  chiefly  beneath  the  walls  and  floor 
of  the  urethra.     They  secrete  mucus. 

Perineimi.  —  The  perineum  properly  signifies  the  parts  bounded 
by  the  outlet  of  the  pelvis,  but  we  generally  apply  it  to  the  tri- 
angular portion  between  the  vagina  and  rectum.  It  is  made 
up  of  muscles  strengthened  with  very  strong  fasciae,  and  covered 
v/ith  skin.  It  is  distensible,  and  stretches  to  a  remarkable  extent 
during  labor.  Nevertheless  it  is  frequently  torn,  and  when  the 
tear  is  of  any  extent,  and  is  not  repaired,  the  vagina  and  uterus 
lose  the  support  afforded  by  it,  and  various  abnormal  conditions 
follow. 

PHYSIOLOGY  OF  THE  FEMALE  GENERATIVE  ORGANS 

Ftmction,  —  The  function  of  the  female  generative  organs  is : 
(1)  the  formation  and  development  of  the  ovum,  (2)  the  reten- 
tion and  sustenance  of  the  fecundated  ovum  until  it  develops 
into  a  mature  foetus  ready  to  live  outside  the  body,  and  (3)  the 
expulsion  of  the  foetus. 

Puberty.  —  Puberty  is  the  period  at  which  the  sexual  organs 
become  matured  and  functional  and  the  girl  develops  into  a 
woman.  The  event  is  not  accomplished  at  once,  but  extends  over 
considerable  time.  The  girl  undergoes  a  gradual  change  in  figure, 
the  hips  broaden,  the  breasts  develop,  and  for  the  first  time  a 
menstrual  flow  is  noticed.  At  first  the  menstrual  periods  are 
scanty  and  irregular,  but  after  a  few  months  they  settle  down 
to  the  characteristic  rate  and  duration.     In  temperate  climates 


452  ANATOMY  FOR   NURSES         [Chap.  XXI 

the  age  at  which  girls  usually  attain  puberty  is  about  foiuteen 
years.  In  southern  countries  it  is  somewhat  earlier,  and  in  the 
arctic  regions,  a  year  or  two  later.  However,  no  fixed  rule  can  be 
given,  as  the  time  of  arrival  at  puberty  varies  with  every  individual, 
depending  on  race,  temperament,  hygiene,  and  general  surround- 
ings. 

The  period  preceding  puberty,  during  which  the  physical  changes 
are  occurring,  is  known  as  the  period  of  adolescence. 

Ovulation.  —  Ovulation  includes  the  process  of  the  develop- 
ment and  maturation  of  the  follicle  and  its  ovum,  and  the  rupture 
of  the  follicle. 

The  commonly  accepted  theory  is  that  about  or  shortly  before 
the  age  of  puberty  the  Graafian  follicles  begin  to  discharge  their 
ova,  and  that  this  process  continues  until  the  menopause.  The 
frequency  with  which  well-developed  ova  are  discharged  is  the 
subject  of  much  dispute.  The  most  conservative  view  is  that 
there  is  one  mature  ovum  discharged  for  each  menstrual  epoch, 
probably  some  days  before  the  period  occurs. 

Menstruation. — Menstruation  consists  of  the  periodical  discharge 
of  bloody  fluid  from  the  uterine  cavity,  "\^^len  once  established 
it  occurs  on  the  average  every  twenty-eight  days  from  the  time  of 
puberty  to  the  menopause,  with  the  exception  of  the  periods  of 
pregnancy  and  lactation.  The  average  duration  is  from  four  to 
five  days  and  the  amount  of  blood  lost  is  about  six  ounces.  The 
menstrual  fluid  consists  of  mucus,  epithelial  cells,  and  blood. 
Some  authorities  are  of  the  opinion  that  the  mucous  membrane  of 
the  uterus  is  normally  shed  during  this  process,  others  do  not 
share  this  opinion. 

The  menopause  or  climacteric.  —  By  menopause  or  climacteric  is 
meant  the  physiological  cessation  of  the  menstrual  flow,  and  the 
end  of  the  period  during  which  the  Graafian  follicles  develop  in 
the  ovaries,  and  consequently  the  end  of  the  child-bearing  period. 
It  is  marked  by  atrophy  of  the  breasts,  uterus,  tubes,  and  ovaries. 
The  age  of  menopause  varies  as  does  the  age  of  puberty  ;  in  general, 
we  may  say  the  earlier  the  puberty  the  later  the  menopause,  and 
vice  versa.  In  temperate  climates  the  average  period  tor  the  arrival 
of  the  menopause  is  at  the  age  of  forty-five  years. 

Changes  in  the  generative  organs  in  connection  with  menstrua- 
tion. —  At  the  beginning  of  menstruation  there  is  a  general  con- 


Chap.  XXI]    THE  ORGANS  OF  GENERATION  453 

gestion  of  the  generative  organs,  including  the  breasts,  accom- 
panied by  more  or  less  discomfort  and  even  pain.  The  mucous 
membrane  of  the  uterus  undergoes  the  following  changes :  (1)  there 
is  marked  hypertrophy  and  congestion  of  the  mucous  membrane, 
(2)  during  menstruation  there  is  capillary  hemorrhage  and  the 
epithelium  of  the  mucous  membrane  is  cast  off,  (3)  following 
menstruation  a  new  epithelium  is  formed  and  the  mucous  mem- 
brane returns  to  its  normal  size. 

Comiection  between  ovulation  and  menstruation.  —  Whether 
ovulation  depends  upon  menstruation  or  menstruation  upon 
ovulation,  or  whether  either  has  any  connection  with  the  other, 
is  a  matter  of  lengthy  controversy.  At  the  present  time  the 
generally  accepted  view  is  that  menstruation  is  dependent  upon 
the  ovaries,  and  that  their  influence  is  exerted  through  the  medium 
of  the  blood.  It  is  thought  that  an  internal  secretion  is  formed  in 
the  ovaries,  possibly  by  the  corpus  luteum.  This  secretion  is 
carried  to  the  uterus  by  the  blood  and  is  responsible  for  the  hyper- 
trophy and  congestion  that  precedes  menstruation.  So  far  it  has 
not  been  possible  to  decide  whether  the  internal  secretion  is  en- 
tirely responsible  for  menstruation,  or  whether  it  is  partly  due  to 
a  power  inherent  in  the  uterine  muscle.  The  fact  that  operations 
for  the  removal  of  the  ovaries  are  followed  by  atrophy  of  the  uterus 
and  cessation  of  menstruation,  supports  the  theory  that  the  ovaries 
are  responsible  for  menstruation. 

Purpose  of  menstruation.  —  The  purpose  of  the  hypertrophy 
and  congestion  of  the  uterus  is  thought  to  be  nature's  way  of 
preparing  the  uterine  walls  for  the  reception  of  the  ovum  should 
it  become  fertilized. 

Mammary  glands.  —  The  two  mammary  glands,  or  breasts, 
may  be  considered  as  accessory  organs  of  generation. 

Function.  —  The  function  of  the  mammary  glands  is  to 
secrete  the  milk  which  is  needed  for  the  nourishment  of  the 
young  infant. 

Location.  —  Each  breast  covers  a  nearly  circular  space  in  front 
of  the  pectoral  muscles,  extending  from  the  second  to  the  sixth 
rib,  and  from  the  sternum  to  the  border  of  the  arm-pit. 

Structure.  —  The  breasts  are  covered  externally  by  skin,  are 
convex  in  shape,  and  about  the  centre  of  the  convexity  a  papilla 
projects,  which  is  called  the  nipple.    The  nipple  contains  the 


454 


ANATOMY  FOR   NURSES  [Chap.  XXI 


openings  of  the  milk  ducts,  and  is  surrounded  by  a  small  circular 
area  of  pink  or  dark  colored  skin,  which  is  called  the  areola.  The 
areola  is  dotted  over  with  projections  formed  by  the  sebaceous 
glands.  They  are  compound  glands,  and  are  divided  by  connec- 
tive tissue   partitions   into  about  twenty  lobes,  each    of   which 


PCCTORALIS    MAJOR 


fibrous  septum 
guano  substance 

Kdipose  tissue 


THIRD   RIB 


AREOLAR   TISSUE 


FIRST 
RIB 


SECOND 
RIB 
PCCTORALIS 

MINOR 
INTERCOSTALES 
SHEATH    OF    PEC- 
TORALIS    MAJOR 


SUPERFICIAL 
FASCIA 


FOURTH    RIB 


LUNG 

ADIPOSE    TISSUE 
HORIZONTAL    PLANt 
OF    NIPPLE 


SIXTH    RIB 


Fig.  209.  —  Bight  Breast  in  Sagittal  Section,  Inner  Surface  of  Outer 
Segment.     (Gerrish.) 

possesses  its  own  excretory  duct,  which  as  it  approaches  the  top 
of  the  breast  dilates  and  forms  a  small  reservoir  in  which  milk  can 
be  stored  during  the  period  when  the  gland  is  active.  Each  duct 
opens  by  a  separate  orifice  upon  the  surface  of  the  nipple.  The 
lobes  are  subdivided,  and  the  small  lobes,  or  lobules,  are  made  up  of 
the  terminal  tubules  of  the  duct,  which  lie  in  a  mesh  of  fibrous 
areolar  tissue  containing  considerable  fat. 


Chap.  XXI]    THE  ORGANS  OF   GENERATION  455 

Blood-vessels  and  nerves.  —  The  mammary  glands  are  well 
supplied  with  blood  brought  to  them  by  branches  of  the  axillary, 
internal  mammary,  and  intercostal  arteries.  The  nerves  are 
chiefly  intercostal  nerves. 

Development  of  the  mammary  glands.  —  The  increase  in  the 
size  of  the  mammary  glands  at  the  time  of  puberty  is  due  to  an 
increased  development  of  the  connective  tissue  and  fat.  The 
glandular  tissue  remains  undeveloped  and  does  not  function  unless 
conception  takes  place.  When  conception  occurs  the  glandular 
tissue  undergoes  a  process  of  gradual  development  that  produces 
marked  changes.  The  breasts  become  larger  and  harder,  the 
veins  on  the  surface  become  more  noticeable,  the  areola  becomes 
enlarged  and  darkened,  the  nipple  becomes  more  prominent,  and 
toward  the  end  of  pregnancy  a  fluid  called  colostrum  can  be 
squeezed  from  the  orifice  of  the  ducts.  After  delivery  the  amount 
of  colostrum  increases  for  a  day  or  two,  and  then  its  composition 
changes  to  that  of  milk. 

The  primary  development  and  later  functioning  of  the  mam- 
mary glands  suggests  an  intimate  connection  between  these  glands 
and  the  uterus  and  ovaries.  The  present  theory  is  that  the  in- 
crease in  the  size  of  the  breasts  at  the  time  of  puberty  is  influenced 
by  the  internal  secretion  of  the  ovaries,  for  if  the  ovaries  are  re- 
moved before  puberty,  the  breasts  do  not  develop,  or  if  the  ovaries 
are  removed  after  puberty,  the  breasts  are  apt  to  atrophy.  The 
development  of  the  glandular  tissue  that  follows  conception  is 
thought  to  be  due  to  some  chemical  substance  that  results  from  the 
metabolism  of  the  foetus.  The  chemical  nature  of  this  substance  is 
not  known,  but  presumably  it  stimulates  the  development  of  the 
gland,  and  also  prevents  secretion,  as  active  secretion  does  not 
commence  until  after  delivery,  and  if  conception  occurs  during  the 
months  of  lactation,  the  character  of  the  milk  is  changed  and  its 
secretion  checked.  The  stimulus  which  causes  the  active  secre- 
tion of  milk  is  thought  to  result  from  the  emptying  of  the  milk 
ducts,  because  of  the  fact  that  when  a  woman  does  not  nurse  her 
infant,  the  secretion  of  milk  is  checked,  and  the  breasts  return 
to  their  usual  size.  The  active  secretion  of  milk  is  also  influenced 
by  the  nervous  system,  and  this  influence  is  probably  exerted 
through  the  vasomotor  nerves  which  control  the  size  of  the  blood- 
vessels, and  consequently  the  amount  of  blood  sent  to  the  gland. 


456 


ANATOMY  FOR  NURSES         [Chap.  XXI 


The  secretion  of  milk.  —  The  secretory  portion  of  the  mammary 
glands  are  the  milk  ducts,  and  these  are  lined  with  secreting  cells. 
Some  of  the  constituents  of  the  milk,  i.e.  water,  salts,  and  sugar, 
are  secreted  by  these  cells  from  the  blood,  but  it  is  thought  that  the 
cells  themselves  disintegrate  and  form  the  proteins  and  fat.  The 
sugar  contained  in  the  milk  is  lactose,  and  the  sugar  of  the  blood 
is  glucose,  so  if  the  first  is  derived  from  the  second,  some  chemical 
change  must  take  place  either  during  or  after  secretion. 

Colostrum  and  milk.  —  The  secretion  of  the  mammary  glands 
during  the  first  few  days  of  lactation  is  called  colostrum.  It  is  a 
thin,  yellowish  fluid,  composed  of  proteins,  fat,  sugar,  salts,  and 
water,  but  not  in  the  same  proportion  as  in  milk.  It  also  contains 
numerous  cells  containing  large  masses  of  fat.  These  are  called 
colostrum  corpuscles,  and  are  secreting  cells  that  are  not  completely 
broken  down. 

Human  milk  is  specially  adapted  to  the  requirements  of  the 
infant  and  so  diflFers  in  some  respects  from  that  of  all  other  animals. 
Cow's  milk  is  most  frequently  substituted  for  human  milk  and  the 
relative  composition  of  the  two  can  be  seen  in  the  following 
table :  — 


Human  (average) 

Cow's  (average) 

Water 

87.30% 
1.50% 
4.00% 
7.00% 
0.20% 

87  00  % 

Proteins      

Fat 

Lactose 

Salts       

4.00% 

4.00% 
4.30% 
0  70% 

In  substituting  cow's  milk  for  human  milk  the  differences  that 
must  be  taken  into  consideration  are  not  only  the  different  relative 
proportions,  but  also  the  following  :  (1)  the  difference  in  the  pro- 
teins ;  the  protein  of  human  milk  is  one-third  caseinogen,  and  two- 
thirds  lactalbumin,  and  that  of  cow's  milk  is  five-sixths  caseinogen 
and  one-sixth  lactalbumin  ;  (2)  the  difference  in  the  curds  formed 
in  the  stomach ;  human  milk  curdles  in  small  flocculi,  and  cow's 
milk  curdles  in  large  heavy  curds ;  and  (3)  the  reaction  of  both 
human  and  cow's  milk  is  amphoteric,  but  cow's  milk  is  more  nearly 
acid  than  human  milk. 


Chap.  XXI]    THE  ORGANS  OF  GENERATION 


457 


Male  generative  organs.  —  The  male  generative  organs  consist  of 
the  following  structures  :  — 

Testes,  two  glandular  organs  which  produce  the  spermatozoa. 

Vas  Deferens 

Seminal  Vesicles 

Ejaculatory  Ducts 

The  Scrotum 

The  Spermatic  Cords 

The  Penis 

The  Urethra 

The  Prostate  Gland 

Cowper's  Glands 

Testes.  —  The  testes  are  two  glandular  organs  which  are  sus- 
pended from  the  inguinal  region  by  the  spermatic  cords,  and  are 
surrounded  and  sup- 
ported by  the  scrotum. 
Each  gland  weighs  from 
five  to  eight  drachms 
(18.5  to  30  grams)  and 
consists  of  two  por- 
tions :  (1)  the  testicle 
proper,  and  (2)  the 
epididymis. 

(1)  The  testicle 
proper  is  ovoid  in  shape 
and  covered  exteriorly 
by  fibrous  tissue  which 
sends  incomplete  parti- 
tions into  the  central 
portion  of  the  gland, 
dividing  it  into  commu- 
nicating cavities.  In 
these  cavities  are  wind- 
ing tubules  which  are 
surrounded  by  blood- 
vessels and  held  together  by  interstitial  tissue.  These  tubules 
inosculate  in  a  sort  of  mesh  (rete  testis)  and  finally  all  unite  in  the 
epidid.>Tnis. 


Fig.  210.  —  Male  Sexual  Apparatus.     (Hall.) 


458  ANATOMY   FOR  NURSES  [Chap.  XXI 

(2)  The  epididymis  is  a  long,  narrow  body  which  Hes  along  the 
posterior  portion  of  the  testicle  and  consists  of  a  tortuous  tubule, 
which  is  lined  with  mucous  membrane,  and  contains  some  muscular 
tissue  in  its  walls.  If  unravelled  it  is  found  to  be  about  twenty- 
feet  (5  metres)  long.  It  connects  the  testicle  proper  with  the  vas 
deferens. 

Function.  —  The  function  of  the  testes  is  the  production  of  sper- 
matozoa. These  spermatozoa  are  the  essential  part  of  the  seminal 
fluid.  The  spermatozoa  originate  in  the  cells  of  the  testes  lining 
the  tubules  which  compose  the  bulk  of  the  testes.  An  internal 
secretion  is  also  supposed  to  be  formed  here. 

Descent  of  the  testes.  —  In  early  fcetal  life  the  testes  are 
abdominal  organs  lying  in  front  of  and  below  the  kidneys.  Dur- 
ing the  process  of  growth  they  are  drawn  downward  through 
the  inguinal  canal  and  shortly  before  birth  are  normally  found  in 
the  scrotum.  Sometimes,  particularly  in  premature  infants,  the 
testis  is  found  in  the  inguinal  canal  or  even  in  the  abdominal 
cavity ;  as  a  rule  it  soon  descends  and  occupies  its  proper  posi- 
tion ;  but  occasionally  it  does  not  descend  and  an  operation  is 
necessary. 

The  vas  deferens.  —  The  vas  deferens  is  a  continuation  of  the 
epididjinis,  and  is  the  excretory  duct  of  the  testicle.  After  a  very 
devious  course  it  joins  the  duct  of  the  seminal  vesicle  at  the  base  of 
the  bladder.  It  consists  of  three  coats,  an  external  areolar,  a 
middle  muscular,  and  an  internal  mucous  coat. 

The  seminal  vesicles.  —  The  seminal  vesicles  are  two  pouches 
which  are  placed  each  one  on  the  outer  side  of  each  vas  deferens, 
between  the  bladder  and  the  rectum.  They  are  pyramidal  in  form, 
with  the  broad  ends  directed  backward  and  widely  separated. 
The  anterior  portions  converge,  become  narrowed,  and  unite  on 
either  side  with  the  corresponding  vas  deferens  to  form  the  ejacu- 
latory  duct. 

Function.  —  The  seminal  vesicles  serve  as  a  reservoir  for  the 
semen,  to  which  they  add  a  secretion  of  their  own. 

The  ejaculatory  ducts.  —  The  ejaculatory  ducts  are  two  in  niun- 
ber,  one  right  and  the  other  left.  They  are  formed  by  the  union 
of  the  seminal  vesicle  and  vas  deferens  of  each  side.  They  run 
downward  and  converge  as  they  descend,  enter  and  pass  between 
the  lobes  of  the  prostate  gland  and  open  into  the  floor  of  the  pros- 


Chap.  XXI]    THE  ORGANS  OF  GENERATION  459 

tatic  portion  of  the  urethra.  Each  has  an  external  areolar,  middle 
muscular,  and  internal  mucous  coat. 

The  scrotum.  —  The  scrotum  is  a  pouch  which  contains  the 
testes  and  a  part  of  each  spermatic  cord.  It  consists  of  a  layer 
of  skin,  and  the  dartos.  The  skin  is  thick  and  dark,  presents  folds 
or  rugae,  is  furnished  with  sebaceous  glands,  and  covered  with  short 
hairs.  The  dartos  is  a  thin  tunic  of  a  reddish  color  consisting  of 
muscular  fibres  and  elastic  tissue  and  containing  numerous  blood- 
vessels. It  is  continuous  with  the  superficial  fascia  of  the  groin 
and  perineum.  It  sends  in  a  partition,  which  separates  the  two 
testes. 

The  spermatic  cord,  —  The  spermatic  cord  forms  the  pedicle 
of  each  testis  and  extends  from  the  internal  abdominal  ring  to  the 
back  of  the  testis.  Each  cord  consists  of  the  vas  deferens,  arteries, 
veins,  lymphatics,  nerves,  the  layers  of  fascia  which  cover  the 
testis,  and  the  remains  of  the  peritoneal  testicular  process.  These 
parts  are  connected  together  by  areolar  tissue. 

The  penis.  —  The  penis  consists  of  three  more  or  less  cylindrical 
bodies  of  erectile  ^  tissue  enclosed  in  fibrous  sheaths.  The  two 
corpora  cavernosa  lie  above  and  receive  between  them  below 
the  corpus  spongiosum,  in  which  the  urethra  is  contained.  The 
glans  penis  is  continuous  with  the  corpus  spongiosum.  The  cov- 
ering of  the  penis  is  of  loose  skin,  but  over  the  glans  penis  and 
lining  the  prepuce  it  resembles  mucous  membrane.  In  this 
region  there  is  an  abundant  subcutaneous  nerve  plexus  and 
numerous  Pacinian  ^  corpuscles,  so  that  it  is  possessed  of  acute 
sensibility. 

The  urethra.  —  The  urethra  extends  from  the  bladder  through 
the  corpus  spongiosum  to  the  end  of  the  penis.  It  is  usually  di- 
vided into  three  parts:  (1)  the  prostatic  urethra,  (2)  the  mem- 
branous urethra,  and  (3)  the  penile  or  spongy  portion.  The 
length  is  usually  given  as  eight  inches  (200  mm,),  a  large  part  of 
which  lies  inside  the  pelvis.  It  is  lined  with  mucous  membrane 
and  furnished  with  numerous  muscular  fibres. 

'  Erectile  tissue  is  found  in  the  clitoris,  penis,  and  the  nipples.  The  form,  size, 
and  consistency  of  this  tissue  change  according  to  the  amount  of  blood  contained 
in  it.  An  increased  amount  of  arterial  blood  causes  swelling,  and  consequent  press- 
ure on,  and  occlusion  of,  the  veins. 

2  Pacinian  corpuscles  are  specialized  nerve-endings  found  in  the  genital  organs 
of  both  sexes,  also  in  the  palms  of  the  hands,  and  the  soles  of  the  feet.  (See  Fig.  177.) 


460  ANATOMY  FOR   NURSES         [Chap.  XXI 

The  prostate.  —  The  prostate  gland  is  situated  in  front  of  the 
neck  of  the  bladder  and  around  the  commencement  of  the  urethra. 
It  resembles  a  chestnut  in  form  and  consists  of  a  dense  fibrous 
capsule  containing  glandular  and  muscular  tissue.  The  glandular 
tissue  consists  of  tubules  which  communicate  with  the  urethra 
by  minute  orifices. 

Function.  —  The  function  of  the  prostate  gland  is  to  secrete 
the  prostatic  fluid,  which  is  an  essential  element  of  the  seminal 
fluid. 

Cowper's  glands.  —  These  are  two  small  bodies  about  the  size 
of  a  pea  situated  one  on  each  side,  adjacent  to,  and  opening  into 
the  membranous  urethra.  They  secrete  a  fluid  which  goes  to 
form  part  of  the  seminal  fluid. 

Puberty.  —  This  occurs  in  the  male  about  a  year  later  than  in 
the  female,  about  fifteen  years  of  age.  At  this  time  the  "  Adam's 
Apple  "  develops,  producing  a  marked  change  in  the  voice,  the  ex- 
ternal genitals  grow  somewhat  rapidly,  hair  grows  on  the  face, 
pubes,  axillae,  and  other  parts  of  the  body,  and  seminal  fluid  begins 
to  be  secreted.  At  the  same  time  sexual  desires  unknown  before 
are  experienced. 

Semen.  —  The  semen  is  a  fluid  derived  from  the  various  sexual 
glands  in  the  male.  The  main  elements  in  this  fluid  are  the  sper- 
matozoa ;  the  other  constituents  are  derived  from  the  seminal 
vesicles,  prostate  gland,  and  Cowper's  glands. 

PHYSIOLOGY  OF   REPRODUCTION 

Reproduction.  —  The  purpose  of  reproduction  is  the  continua- 
tion of  the  species,  and  is  accomplished  by  means  of  the  reproduc- 
tive organs,  whose  importance  is  in  their  adaptation  to  produce 
another  being. 

Impregnation.  —  The  term  impregnation  or  fertilization  is  ap- 
plied to  the  union  of  the  spermatozoon  or  male  cell,  with  the  ovum 
or  female  cell. 

The  ovum.  —  The  ovum  is  a  minute  globular  cell  about  j^-g  inch 
(0.2  mm.)  in  diameter.  The  component  parts  have  received 
special  names. 

The  ceU-wall  is  a  thick,  surrounding  envelope,  or  membrane, 
called  the  vitelline  membrane. 


Chap.  XXI]     THE  ORGANS  OF  GENERATION  461 

The  cell-body  is  a  mass  of  cytoplasm  filled  with  fatty  and 
albuminous  granules,  and  usually  called  the  vitellus. 

The  cell  nucleus,  or  germinal  vesicle,  is  a  transparent,  sharply 
outlined  nucleus,  embedded  in  the  vitellus. 

The  nucleolus,  or  germinal  spot,  is  a  small,  dark  spot  situated 
in  the  fluid  nucleus. 

The  cell-body  or  cytoplasm  contains  the  food  material,  and  the 
nucleus  contains  chromatin  material.  Chromatin  is  of  special 
interest  because  it  is  believed  that  it  is  through  the  chromatin 
material  that  hereditary  characteristics  are  transmitted. 

The  spermatozoon.  —  The  spermatozoon  is  the  male  generative 
cell  and  its  function  is  to  fertilize  the  ovum  and  produce  impregna- 
tion. It  is  much  smaller  than  the  ovum,  being  only  5^  inc^  (0.1 
mm.)  in  length.  It  consists  of  an  elliptical  head,  a  rod-shaped 
middle  piece,  and  a  tail  that  gradually  tapers.  The  head  contains 
nuclear  material  and  chromatin.  There  is  an  active  vibratory  motion 
of  the  tail  which  allows  it  quite  free  motion  in  the  seminal  fluid. 
Because  of  this  free  motion  the  spermatozoa  are  able  when  depos- 
ited in  the  vagina  to  travel  upward  into  the  uterus,  and  into 
the  tubes  even  against  the  current  produced  by  the  cilia  of  the 
tubes. 

Site  of  impregnation.  —  It  is  thought  that  impregnation  takes 
place  in  the  Fallopian  tubes.  When  the  Graafian  follicle  ruptures 
and  an  ovum  escapes  into  the  abdominal  cavity,  the  current  pro- 
duced by  the  cilia  of  the  tubes  is  thought  to  draw  it  into  the  tube. 
Once  in  the  tube  the  peristaltic  action  of  the  tube  and  the  action 
of  the  cilia  propel  it  slowly  along  to  the  uterus.  If  the  ovum  does 
not  become  impregnated  it  passes  into  the  uterus  and  is  cast  off 
in  the  next  menstrual  flow.  If,  however,  it  comes  in  contact  with 
the  spermatozoon  in  its  passage  through  the  tube,  the  spermato- 
zoon enters  the  ovum  and  segmentation  or  the  process  of  cell  divi- 
sion begins  at  once. 

Segmentation.  —  After  the  union  of  these  two,  the  cell  rapidly 
divides  into  two,  each  of  these  two  into  other  two,  and  so  forth, 
until  we  have  a  number  of  cells  where  formerly  there  was  one.  At 
this  stage  the  collection  of  cells  is  called  the  blastoderm.  Grad- 
ually these  cells  which  constitute  the  blastoderm  become  arranged 
in  three  layers,  the  outer  called  the  ectoderm,  an  inner  called  the 
entoderm,  and  a  middle  layer  called  the  mesoderm.     (See  page  27.) 


462  ANATOMY  FOR   NURSES         [Chap.  XXI 

The  passage  of  the  fertiUzed  ovum  through  the  tubes  requires 
about  eight  days,  and  during  this  time  many  thousands  of  cells 
are  formed  and  enclosed  in  a  sac  called  the  amnion.  The  collection 
of  cells  surrounded  by  the  amnion  is  called  an  embryo.  After 
entering  the  uterus  the  embryo  attaches  itself  to  the  mucous  mem- 
brane, in  the  upper  portion,  usually  near  the  opening  of  the 
Fallopian  tubes. 

Changes  in  the  uterine  lining.  —  The  preparation  of  the  mucous 
membrane  of  the  uterus  for  the  reception  of  the  impregnated  ovum 
includes  changes  that  are  similar  to  those  that  precede  menstrua- 
tion. The  mucous  membrane  becomes  softer,  thicker,  and  highly 
congested.  In  this  condition  it  is  known  as  the  decidua  vera,  and 
the  point  to  which  the  ovum  becomes  attached  and  whicji  later 
develops  into  the  placenta  is  called  decidua  scrotina. 

Intrauterine  growth.  —  During  the  period  of  intrauterine  life 
growth  takes  place  rapidly.  From  the  union  of  the  ovum,  which  is 
ll^  inch  (0.2  mm.)  in  diameter,  and  the  spermatozoon,  which  is 
much  smaller,  there  is  developed  in  two  weeks'  time  an  embryo 
which  is  about  the  size  of  a  bean.  At  the  end  of  four  weeks  it  is 
the  size  of  a  walnut,  and  at  four  months  it  is  called  a  foetus,  because 
it  has  the  appearance  of  a  human  being,  with  well-developed  eyes, 
fingers  and  toes  separated,  and  the  external  genitals  sufficiently 
formed  to  determine  the  sex.  The  usual  duration  of  pregnancy  is 
nine  lunar  or  ten  calendar  months,  but  at  the  end  of  sLx  months  the 
foetus  is  sufficiently  developed  to  live  outside  the  mother's  body, 
but  it  is  fragile  and  requires  a  great  deal  of  care. 

For  further  details  on  the  subject  of  reproduction  the  student  is 
referred  to  standard  works  on  physiology  and  obstetrics. 


Chap.  XXI] 


SUMMARY 


463 


SUMMARY 


Female 

Generative 

Organs 


Internal 
organs 


External 
organs 


Ovaries 


Ovaries  —  two  glandular  organs  in  which  the  ova 

are  formed. 
Fallopian  tubes  —  two  canals  through  which  the 

ova  reach  the  uterine  cavity. 
Uterus  —  a  hollow,  pear-shaped   organ  which 

receives  the  ovum. 
Vagina  —  a  canal  that  extends  from  the  uterus 

to  the  vulva. 

Mons  Veneris  —  a  cushion   of  areolar  fibrous 

and  adipose  tissue,  in  front  of  pubic  bones, 

covered  with  skin  and  after  puberty  with  hair. 

Labia  majora  —  two  folds  that  extend  from  the 

mons  Veneris  to  within  an  inch  of  the  anus. 

Labia  minora  —  two  folds  situated  between  the 

labia  majora. 
CUtoris  —  small  body,  situated  at  apex  of  the 
triangle  formed  by  junction  of  labia  minora. 
Well  supplied  with  nerves  and  blood-vessels. 
Hymen  —  fold  of  mucous  membrane  that  sur- 
rounds vaginal  orifice. 

'  Vulvo-vaginal  —  oval  bodies  situated 

on  either  side  of  the  vagina. 
Urethral  —  glands  found  chiefly  be- 
neath the  walls  and  floor  of  urethra. 
Two  almond-shaped  glandular  bodies. 
Situated  in  posterior  fold  of  broad  ligament. 

To  uterus  —  by  hgament  of  ovary. 
To  tubes  —  by  fimbriae. 
If  inches  long, 
f  inch  wide. 
[  I  inch  thick. 
Weight  —  1-2  drachms. 

Fibrous  tissue. 
Blood-vessels, 
Lymphatics. 
Nerves. 
Graaf- 
ian 
fol- 
licles 
Covering  of  germinal  epithelium. 
J  Produce,  develop,  mature,  and  discharge  ova. 
\  Form  an  internal  secretion. 


Glands 


Attached 


Size 


Structure 


Stroma " 


1.  Outer  coat  fibrous  tissue. 

2.  Inner  layer  of  cells  contain  ovum. 


Function 


464 


ANATOMY   FOR  NURSES         [Chap.  XXI 


Fallopian 
Tubes 


Uterus- 


V^agina 


Location 


Divisions     < 


Three 

coats 


Enclosed  in  layers  of  broad  ligament. 

Extend  from  upper  angles  of  uterus  to  sides  of 

pelvis. 
1.  Isthmus  —  or  inner  constricted  portion  near 

portion    which    curves 


Divisions 


Three 
coats 


Blood- 
vessels 


Isthmus  - 
uterus. 
Ampulla  —  dilated 

over  ovary. 
Infundibulum  —  trumpet-shaped    extremity 

—  fimbriae. 
External,  or  serous. 
Middle,  or  muscular. 

Internal,  or  mucous,  arrranged  in  longitudinal 
folds  and  covered  with  cilia. 
Function  —  Convey  ova  to  uterus. 

Hollow,  thick-walled  organ,  placed  in  pelvis  between  bladder 
and  rectum. 
Fundus  =  rounded  upper   portion,  above   the 

entrance  of  the  tubes. 
Body  =  portion  below  fundus,  above  neck. 
Cervix  =  lower  and  smaller  portion  which  ex- 
tends into  vagina. 

■  External,  or  serous,  derived  from  peritoneum. 

{Circular  fibres  "i  Interlaced     in 

Longitudinal  fibres  >     every  direc- 
Spiral  fibres  J      tion. 

Mucous  membrane,  lines  the  uterus. 
Uterine  arteries  from  internal  iliacs. 
Ovarian  arteries  from  aorta. 
Remarkable  for  tortuous  course  and  frequent 
anastomoses. 

■  Broad,  or  lateral  —  two  layers  of  serous  mem- 
brane. 

Round  —  two  fibro-muscular  cords. 
Utero-sacral  —  two  partly  serous,  partly  mus- 
cular, ligaments. 
Anterior  —  peritoneal  floor  of  the  utero-vesical 

pouch. 
Recto-vaginal  —  peritoneal  floor  of  the  recto- 
vaginal pouch. 
Function  —  To  receive  ovum,  and  if  it  becomes  fertiUzed  to 

retain  it  until  developed  and  then  to  expel  it. 
Canal  —  Ebctends  from  uterus  to  vulva. 
C  Outer  coat  is  fibrous. 
{  Middle  coat  is  muscular. 
[  Mucous  coat,  or  lining,  arranged  in  rugae. 
Location  —  Placed  between  urethra  and  rectum. 


Ligaments  ' 


Three 
coats 


Chap.  XXI] 


SUMMARY 


465 


Physiology 
of    Gen- 
erative 
Organs 


Changes     in 
connection 
with       men- 
struation 


Connection 
between  ovu- 
lation and 
menstruation 


Mammary 
Glands 


Function     (  ^o^^^ation  and  development  of  ovum. 

I  Retention  and  sustenance  of  fecundated  ovum. 
Puberty  —  Age  at  which  sexual  organs  become  matured  and 
functional.     Girl  changes  to  woman. 

Ovulation  /  ^^°^*^^^  ^^  development  and  maturation  of  fol- 
[  licle  and  ovum,  and  discharge  of  ovum, 
f  A  flow  of  blood  from  the  uterus.  Occurs  on  an 
average  every  twenty-eight  days.  Extends 
from  puberty  (14  years)  to  the  menopause, 
or  climacteric  (about  45  years).  This  period 
represents  the  child-bearing  period  of  a 
woman's  life. 

1.  General  congestion  of  genera- 
tive organs  including 
breasts. 

2.  Hypertrophy  and  congestion 
Menstrua-  I  connection      I  of   mucous   membrane    of 

tion  1  with       men-  I  uterus. 

Capillary  hemorrhage.     Epi- 
thelium is  cast  off. 
Following  menstruation  a  new 
epithehum  is  formed. 
'  Probably  dependent  on  internal 
secretion  of  ovaries,  and  pos- 
sibly is  aided  by  power  in- 
herent in  uterine  muscle. 
Purpose  —  Nature's  way  of  preparing  uterine 
I      walls  for  reception  of  fertilized  ovum. 
I  Menopause  —  Physiological  cessation  of  the  menstrual  flow. 
Accessory  organs  of  generation. 
Function  —  To  secrete  milk  to  nourish  infant. 
Location     /  ^^^nd  from  second  to  sixth  rib. 
I  Sternum  to  arm-pit. 

'  Outer  surface  convex  —  papilla  projects  from 
centre  —  called  nipple  —  contains  openings 
of  milk  ducts.  Nipple  surrounded  by  areola. 
Consists  of  connective  tissue  framework  which 
divides  the  gland  into  about  twenty  lobes. 
Lobes  are  subdivided  into  lobules. 
Lobules  are  made  up  of  the  terminal  tubules 

of  the  duct. 
Each  lobe  possesses  its  own  excretory  duct, 
I  which  is  called  lactiferous  and  is  sacculated. 

r  Axillary. 

<  Internal  mammary. 
I  Intercostal. 


Structure 


Blood- 
vessels 


2h 


466 


ANATOMY  FOR  NURSES 


[Chap.  XXI 


Mammary 
Glands 


Colostrum 


MUk 


Nerves 


Develop- 
ment 


Secretion 
of  milk 


Male  Gen- 
erative 
Organs 


Intercostal. 

Primary  development  at  time  of  puberty,  prob- 
ably due  to  internal  secretion  of  ovaries. 

Functional  development  follows  conception, 
probably  due  to  chemical  substances  that 
result  from  metabolism  of  foetus.  Active  se- 
cretion stimulated  by  emptying  milk  ducts 
and  influenced  by  nervous  system. 

Water  \ 

Salts  >  Secreted  from  blood. 

I  Sugar  J 

Proteins 

Fat 


Formed    by    disintegration    of 
cells  lining  lactiferous  tubules. 
Thin  yelIo\A'ish  fluid  secreted  during  first  few  days  of  lactation. 


Composi- 
tion 


Composi- 
tion 


Proteins 
Fat     . 
Sugar 
Salts  . 
Water 


Water  . 
Proteins 
Fat  .  . 
Lactose 

Salts 


Human 
87.30  % 
1.50% 
4.00  % 
7.00  % 
0.20  % 


5.71  per  cent 
2.04  per  cent 
3.74  per  cent 
0.28  per  cent 
88.23  per  cent 
100.00  per  cent 
Cow's 


Differ- 
ences 


100.00  % 
Diff'erent  relative  proportions. 

Human  /  Caseinogen  § 


87.00  % 
4.00  % 
4.00  % 
4.30  % 
0.70  % 
100.00  % 


Difference  in 
proteins 


Difference  in 
reaction 


Cow's 


\  Lactalbumin  |. 
J  Caseinogcn  ^. 
I  Lactalbumin  |. 
Difference  in  J  Human  —  small  flocculi. 
curds  \  Cow's  —  heavy  curds. 

Human  —  amphoteric. 
Cow's  —  amphoteric,  but  more 
nearly  acid. 


Testes. 

Vas  deferens. 

Seminal  vesicles. 

Ejaculatorj''  ducts. 

The  scrotum. 

Spermatic  cords. 

The  penis. 

The  urethra. 

The  prostate  gland. 

Cowper  glands. 


Chap.  XXI] 


SUMMARY 


467 


Testes 


Structure 


Location 


Function 


Two  glandular  organs  which  produce  the  spermatozoa. 

Testicle  proper  —  ovoid  body  covered  by  fibrous 
tissue.     Central  portion  consists  of  irregular 
cavities  filled  with  seminiferous  tubules  and 
blood-vessels. 
Epididymis  —  tortuous     tubule,    forms    long, 
narrow  body  which  lies  along  posterior  por- 
tion of  testes. 
(In  early  foetal  life  in  abdomen  below  kidneys. 
Before  birth  is  normally  drawn  downward  to 
scrotum,  and  is  suspended  by  spermatic  cord, 
f  Production  of  spermatozoa. 
I  Production  of  internal  secretion. 
Vas  Deferens  —  Continuation  of  epididymis,  and  serves  to  connect  the 
epididymis  and  the  seminal  vesicle  of  each  side. 
Two  pouches  located  between  bladder  and  rectum  on  outer 
side  of  each  vas  deferens.     Connect  vas  deferens  with 
ejaculatory  duct. 
Function  —  Serve  as  reservoirs  for  semen,  to  wliich  they  add 

a  secretion  of  their  own. 
Formed  by  union  of  seminal  vesicles  and  vas  deferens  of 

each  side. 
Run  downward,  converge,  pass  between  lobes  of  prostate  gland 
and  open  into  the  floor  of  the  prostatic  portion  of  the  urethra . 
Pouch  wliich  contains  testes  and  part  of  each  spermatic  cord. 
Covered  with  thick  dark  skin. 
Dartos  —  reddish  tunic  under  skin,  consists  of 
muscular  and  elastic  tissue  with  numerous 
blood-vessels.     Divided  by  septum  into  two 
halves. 
'  Consists  of  the  vas  deferens,  arteries,  veins,  lymphatics, 
nerves,  and  layers  of  fascise  connected  by  areolar  tissue 
and  serving  as  pedicle  for  testes. 
Extends  from  the  internal  abdominal  ring  to  the  back  of 
the  testes. 
(  Consists  of  three  cylindrical  J  1.  Corpora  cavernosa. 
I      bodies  of  erectile  tissue       I  2.  Corpus  spongiosum. 
{  Contains  urethra  wliich  extends  from  bladder  to  the  end  of 
penis. 
Covered  with  skin  and  mucous  membrane. 
'  Extends  from  the  bladder  through  the  corpus  spongiosum 
to  the  end  of  the  penis.     Length  8  inches. 
(  Prostatic  portion. 
Divisions    <  Membranous  portion. 

I  Penile  or  spongy  portion. 
Consists      f  Mucous  fining. 

of  I  Numerous  muscular  fibres. 


Seminal 
Vesicles 


Ejaculatory 
Ducts 


Scrotum 


Structure 


Spermatic 
Cords 


Penis 


Urethra 


468 


ANATOMY  FOR   NURSES         [Chap.  XXI 


The  Pros- 
tate 


Cowper's 
Glands 


Puberty 
Semen 


Reproduc- 
tion 


Consists 
of 


tion 


Ovum 


Situated  in  front  of  the  neck  of  the  bladder  and  around  the 

commencement  of  urethra. 
Shape  —  resembles  chestnut. 

Fibrous  capsule  containing  glandular  and  mus- 
cular tissue.     Glandular   tissue   consists  of 
tubules  which  empty  into  urethra. 
Function  —  Secretion  of  prostatic  fluid. 
Located  one  on  each  side  of  membranous  urethra  into  which 

they  empty.    About  the  size  of  a  pea. 
Function  —  Secretion  of  a  fluid  wliich  forms  part  of  seminal 

fluid. 
Age  at  which  sexual  organs  become  matured  and  functional. 
Boy  changes  to  a  man. 
j  Fluid  derived  from  the  various  sexual  glands  in  the  male. 
I  Spermatozoa  are  the  main  elements. 
Function  —  Produce  another  being. 
Impregna-  f  Union  of  spermatozoon  and  ovum. 
\  Occurs  in  Fallopian  tubes. 
Globular  cell  fonned  in  ovaries,   jls   inch  in 
diameter. 

Cell- wall  =  zona  pellucida. 
CeU-body  =  cjiioplasm,  serves  as 

food. 
Cell  nucleus  =  germinal  vesicle, 

contains  chromatin. 
.  Nucleolus  =  germinal  spot. 
A  long,  narrow  cell  formed  in  testes,  ^Jo  of  an 
inch  in  length. 

■  EUiptical  head  which  contains 
nuclear  material  and  chroma- 
Consists  of     {      tin. 

Rod-shaped  centre  piece. 
Tail. 
Capable    of    independent    motion    in    a    fluid 

medium. 
Function  to  fertilize  o^^im. 
Di\'ides  into  many  cells  surrounded  by  amnion 
and  called  embryo.     Attaches  itself  to  upper 
part  of  uterine  ca\'ity  in  soft  mucous  mem- 
brane prepared  for  its  reception. 
(Entoderm. 
Mesoderm. 
Ectoderm. 
Two  weeks  —  size  of  a  bean. 
Four  weeks  —  size  of  a  walnut. 
Four  months  —  foetus  —  human  characteristics 
are  marked. 


Consists 


Sperma- 
tozoon 


Develop- 
ment of  {  Embryo 
ovum 


METRIC  SYSTEM 


I  1  Inch 


4  I  5 

Centimetres 


The  area  of  the  figure  within  the  heavy  lines  is  that 
of  a  square  decimetre.  A  cube,  one  of  -whose  sides  is 
this  area,  is  a  cubic  decimetre  or  litre.  A  litre  of  water 
at  the  temperature  of  4°  C.  weighs  a  kilogramme. 

A  litre  is  2.11  pints  or  33.81  ounces.  A  pint  is  0.473 
of  a  litre.     (Liquid  measure.) 

A  litre  is  1.76  pint.  A  pint  is  0.568  litre.  (Dry 
measure.) 

The  smaller  figures  in  dotted  lines  represent  the  areas 
of  a  square  centimetre  and  of  a  square  inch. 

A  cubic  centimetre  of  water  at  4'^  C.  weighs  a  gramme. 


1  Metre  =  39. .370432  inches. 

1  Decimetre   =    3.937043  inches. 
1  Centimetre  =      .393704  inch. 
1  Millimetre  =     .039370  inch. 


1  Gramme 
1  Decigramme 
1  Centigramme 
1  Milligramme 
1  Dekagramme 
1  Ilektogramme 
1  Kilogramme 
1  Kilogramme 
1  Kilogramme 


15.432  grains. 
1.543  grains. 
.154  grain. 
.015  grain. 
154.323  grains. 
1543.235  grains. 
15432.350  grains. 
35.274  ounces. 
2.204  pounds. 


Avoirdupois  weights  are  used  in  weighing  the  organs  of  the  body.    One  ounce 
avoirdupois  =  28.35  grammes. 


469 


GLOSSARY 

Abdo'men.     [From  the  Lat.  abdo,  to  "  conceal."]     The  largest  cavity 

of  the  body,  containing  the  liver,  stomach,  intestines,  etc. ;  the  belly. 
Abdu'cens.     [From  the  Lat.  ab,  "  from,"  and  duco,  to  "  lead."]     A  term 

applied  to  the  sixth  pair  of  cranial  nerves  which  supply  the  external 

recti  (abductor),  muscles  of  the  eye. 
Abduc'tion.     [From  the  Lat.  ab,  "  from,"  and  duco,  to  "  lead."]    Drawn 

away  from  the  middle  line  of  the  body. 
Absorp'tion.     [From  the  Lat.  ab,  "  from,"  and  sorbeo,  to  "  suck  up."] 

The  process  of  taking  up  into  the  vascular  system  either  digested  food 

from  the  alimentary  canal,  or  other  substances  from  the  various 

tissues. 
Acetab'ulum.     [From  the  Lat.  acetum,  "  vinegar."]    A  name  given  to 

the  cup-shaped  cavity  in  the  os  innominatum,  resembling  in  shape  an 

old-fashioned  vinegar  vessel. 
Acromeg'aly.     [From  the  Gr.  akron,  an  "  extremity,"  and  megas,  "  great."] 

A  disease  characterized  by  an  overgrowth  of  the  extremities  and  the 

face  as  well  as  the  soft  parts. 
Acro'mion.     [From  the  Gr.  akron,  "  summit,"  and  omos,  the  "  shoulder."] 

The  triangular-shaped  process  at  the  summit  of  the  scapula. 
Adduc'tion.     [From  the  Lat.  ad,  "  to,"  and  duco,  to  "  lead."]     Brought 

to  or  nearer  the  middle  line  of  the  body. 
Ad'enoid.     [From  the  Gr.  aden,  a  "  gland,"  and  eidos,  "  form,"  or  "  re- 
semblance."]    Pertaining  to,  or  resembling  a  gland. 
Ad'ipose.     [From  the  Lat.  adeps,  "  fat."]     Fatty. 
Adre'nal.     [From  the  Lat.  ad,  "to,"  and  ren,  the  "kidney."]    Same  as 

supra-renal.     A  small  gland  situated  on  the  top  of  the  kidneys. 
Afferent.     [From  the  Lat.  ad,  "  to,"  and  Jero,  to  "  bear,"  to  "  carry."] 

Bearing  or  carrying  inwards,  as  from  the  periphery  to  the  centre. 
Agminated.     [From  the  Lat.  agmen,  a  "  multitude,"  a  "  group."]    Ar- 
ranged in  clusters,  grouped  together  as  the  agminated  glands  of  Peyer 

in  the  small  intestine. 
Akine'sis.     [From  the  Gr.  a,  "without,"  and  kinesis,  "motion."]    Without 

motion.     Fission  or  direct  division  of  cells. 

471 


472  GLOSSARY 

Albu'mins.  [From  the  Lat.  albus,  "  white."]  Thick,  viscous  substances 
containing  nitrogen,  that  are  soluble  in  water,  dilute  acids,  dilute 
salines,  and  concentrated  solutions  of  magnesium  sulphate  and  so- 
dium chloride.  They  are  coagulated  by  heat  and  strong  acids.  Ex- 
amples are :  egg  albumin  and  serum  albumin  of  blood. 

Albuminu'ria.  [A  combination  of  the  words  "  albumin  "  and  "  urine."] 
Presence  of  albumin  in  the  urine. 

Alimentary.  [From  the  Lat.  alimentum,  "food."]  Pertaining  to  ali- 
ment, or  food. 

Alve'oll.  Plural  of  alveolus.  [From  the  Lat.  alveolus,  a  "  little  hollow."] 
Any  little  cell,  pit,  cavity,  fossa,  or  socket.  Socket  of  a  tooth  or  an 
air-cell. 

Amoe'ba.  [From  the  Gr.  ameiho,  to  "  change."]  A  single-celled  organ- 
ism, which  is  constantly  changing  its  form  by  protrusions  and  with- 
drawals of  its  substance. 

Amphiarthro'sis.  [From  the  Gr.  ampho,  "  both,"  and  arthron,  a  "  joint."] 
A  mixed  articulation ;  one  which  allows  slight  motion. 

Amphoteric.  [From  the  Gr.  amphoteros,  "  both."]  Partly  acid  and  partly 
alkaUne  in  reaction ;  having  t;he  power  of  turning  red  Utmus  paper 
blue,  and  blue  htmus  paper  red. 

Ampul'la.  [From  the  Lat.  ampulla,  a  "  globular  vessel."]  The  dilated 
part  of  a  canal. 

Amylop'ins.  [From  the  Gr.  amylum,  "  starch,"  and  opsis,  "  appear- 
ance."] An  enzjone  of  the  pancreatic  juice  that  has  the  power  to 
change  starch  into  malt  sugar,  or  maltose.     Same  as  diastase. 

Anabol'ism.  [From  the  Gr.  anabole,  a  "  thromng  up."]  The  process 
by  means  of  which  simpler  substances  are  built  up  into  more  complex 
substances. 

Anaesthe'sia.  [From  the  Gr.  a,  an,  "  without,"  and  aisthanomai,  to 
"  perceive,"  to  "  feel."]    A  condition  of  insensibihty. 

Anastomo'sis.  [From  the  Gr.  ana,  "  by,"  "  tlirough,"  and  stoma,  a 
"  mouth."]     Conmiunication  of  branches  of  vessels  with  one  another. 

An'nular.  [From  the  Lat.  aymulus,  a  "  ring."]  Ring-like,  such  as  the 
Ugaments  found  at  some  of  the  joints. 

Aor'ta.  [From  aorte,  to  "  carry."]  The  great  artery  that  carries  blood 
from  the  left  ventricle  of  the  heart. 

Apnoe'a.  [From  the  Gr.  a,  "  without,"  and  pnwa,  "  breath."]  Absence 
of  breathing. 

Aponetiro'sis.     [From  the  Gr.  apo,  "from,"  and  neuron,  a  "sinew"  or 


GLOSSARY  473 

"  tendon."]    A  flat  wide  band  of  fibrous  tissue  which  is  attached  to  a 

muscle. 
Arach'noid.     [From  the  Gr.  arachne,  a  "  spider,"  a  "  spider's  web,"  and 

eidos,  "  form,"  or  "  semblance."]     Resembling  a  web.     The  middle 

of  the  three  membranes  of  the  brain  and  spinal  cord. 
Arboriza'tions.     A  growth  or  an  appearance  resembhng  the  figure  of  a 

tree  or  plant. 
Are'olar.     [From  the   Lat.  areola,  a  "  small  space,"  dim.  of  area.]    A 

term  apphed  to  a  connective  tissue  containing  small  spaces ;  also  to 

the  colored  area  surrounding  the  nipple. 
Arrec'tor.     [From  the  Lat.  arrectus,  "  set  up  erect."]     That  which  arrects. 

The  arrector  of  the  hair. 
Arte'rioles.     [Arteriola,  dim.  of  Lat.  arteria,  ^'  artery."]    A  small  artery. 
Arteriosclero'sis.     [See  artery  below.    Lat.  scleroticus,  from  Gr.  skleroo,  to 

"  harden."]     Hardening  of  the  arteries. 
Ar'tery.     [From  the  Gr.  aer,  "  air,"  and  tereo,  to  "  keep."]     Literally, 

an  air-keeper  (it  being  formerly  believed  that  the  arteries  contained 

air).    A  blood-vessel  which  carries  blood  from  the  heart. 
Arthro'dia.    [From  the  Gr.  arthron,  a  "  joint."]    A  variety  of  movable  joint. 
Articula'tion.     [From  the  Lat.  articulus,  "  a  joint."]     The  more  or  less 

movable  union  of  bones,  etc. ;  a  joint. 
Asphyx'ia.     [From  the  Gr.  a,   "  without,"  and  sphyxis,  the  "  pulse."] 

Literally,  without  pulse.     Condition  caused  by  non-oxygenation  of 

the  blood. 
Assimila'tion.     [From  the  Lat.   ad,   "  to,"   and  similis,   "  Uke."]    The 

conversion  of  food  into  living  tissue. 
At'las.     The  first  cervical  vertebra  by  which  the  head  articulates  with 

the  spinal  column,  so  called  because  it  supports  the  head  as  Atlas 

was  fabled  to  support  the  world  on  his  shoulders. 
At'rophy.     [From  the  Gr.  a,  "  without,"  and  trophe,  "  nourishment."] 

Wasting  of  a  part  from  lack  of  nutrition. 
Aud'itory.     [From  the  Lat.  audio,  auditum,  to  "  hear."]     Pertaining  to 

the  sense  or  organ  of  hearing. 
Augmenta'tion.     The  act  of  increasing  or  making  larger. 
Aur'icle.     [From  the  dim.  of  Lat.  auris,  the  "  ear."]     A  little  ear,  a  term 

apphed  to  the  ear-shaped  cavities  of  the  heart,  also  to  the  expanded 

portion  of  the  external  ear. 
Automat'ic.     [From  the  Gr.  automatos,  "self -moving."]     Not  voluntary, 

not  under  the  control  of  or  affected  by  voUtion. 


474  GLOSSARY 

Az'ygos.  [From  the  Gr.  a,  "  without,"  and  zygos,  a  "  yoke."]  Without 
a  fellow ;  hence,  unpaired,  single. 

Bi'ceps.  [From  the  Lat.  bis,  "  twice,"  and  caput,  the  "  head."]  A  term 
apiilicd  to  muscles  having  a  double  origin  or  two  heads. 

Bicus'pid.  [From  the  Lat.  bis,  "  twice,"  and  cuspis,  the  "  point  of  a 
spade."]    Having  two  points  or  flaps. 

Blas'toderm.  [From  the  Gr.  blastos,  a  "  bud,"  and  derma,  "  skin."]  The 
primitive  membrane  or  layer  of  cells  resulting  from  the  subdivision 
of  the  germ. 

Brach'ial.     [From  the  Lat.  brachium,  the  "  arm."]     Belonging  to  the  arm. 

Brachio-cephal'ic.  [From  the  Lat.  brachium,  the  "  arm,"  and  cephalicus, 
"  of  or  pertaining  to  the  head."]  Of  or  pertaining  both  to  the  upper 
arm  and  the  head ;  as  the  brachio-cephalic  (innominate)  artery  and 
veins. 

Bron'chi,  pi.  of  Bronchus.  [From  the  Gr.  bronchos,  the  "  wind  pipe."]  The 
two  main  branches  of  the  trachea. 

Bron'chioles.     A  small  bronchial  tube. 

Buc'cal.  [From  the  Lat.  bucca,  the  "  cheek."]  Pertaining  to  the  mouth 
or  cheeks. 

Buc'cinator.  [From  the  Lat.  buccinare,  "  blow  a  trumpet."]  The  trum- 
peter's muscle.  A  thin,  flat  muscle  that  helps  to  form  the  wall  of 
the  cheek. 

Bur'sal.  [From  the  Gr.  bursa,  a  "  bag."]  Pertaining  to  bursce,  mem- 
branous sacs. 

But'tock.  The  part  at  the  back  of  the  hip,  which  in  man,  forms  one  of 
the  protuberances  on  which  he  sits. 

Butyr'ic  Acid.  [From  the  Lat.  butyrum,  "  butter."]  A  colorless  liquid 
having  a  strong  rancid  smell  and  acrid  taste.     C3H7COOH. 

Cae'cum.     [From  the  Lat.  ccecus,  "  bUnd."]    The  blind  gut. 
Calca'neum.     [From  the  Lat.  calx,  the  "  heel."]    The  bone  of  the  heel. 
Cal'culi,  pi.  of  Cal'culus.    [From  the  Lat.  calculus,  "  a  pebble."]     Stones. 
Caly'ces,  pi.  of  Ca'lyx.     [From  the  Gr.  kalyx,  a  "  cup."]     Anatomists 

have  given  this  name  to  small  cup-Uke  membranous  canals,  which 

surround  the  papillae  of  the  kidney,  and  open  into  its  pelvis. 
Canalic'ulus,  pi.  Canalic'uli.     [Dim.  of  Lat.  canalis,  a  "  channel."]     A 

small  channel,  or  vessel. 
Can'cellated.     [From  the  Lat.  canccZ/MS,  "  lattice-work."]    A  term  used 

to  describe  the  spongy  lattice-work  texture  of  bone. 


GLOSSARY  475 

Ca'nine.  [From  the  Lat.  canis,  a  "  dog."]  Name  given  to  the  third 
tooth  on  each  side  of  the  jaw;  in  the  upper  jaw  it  is  also  known  as 
the  eye-tooth,  pointed  hke  the  tusks  of  a  dog. 

Can'thus.  [From  the  Gr.  kanthos,  the  "  angle  of  the  eye."]  The  angle 
formed  by  the  junction  of  the  eyelids,  the  internal  being  the  greater, 
the  external  the  lesser,  canthus. 

Cap'illary.  [From  the  Lat.  capillus,  "  hair."]  A  minutely  fine  vessel,  re- 
sembling a  hair  in  size. 

Car'dio-inhib'itory.  [From  the  Gr.  kardia,  "  heart,"  and  inhibere,  to 
"  restrain."]     An  agent  which  restrains  the  heart's  action. 

Carot'ids.  [Perhaps  from  the  Gr.  karos,  "  stupor,"  because  pressing  on 
them  produces  stupor.]  The  great  arteries  conveying  blood  to  the 
head. 

Car'pus.  [From  the  Gr.  karpos,  the  "  wrist."]  The  assemblage  of  bones 
forming  the  wrist. 

Car'tilage.  [From  the  Lat.  cartilago,  "  gristle."]  A  soUd  but  flexible  ma- 
terial, forming  a  part  of  the  joints,  air-passages,  nostrils,  etc.    Gristle. 

Ca'seinogen.  [From  the  Lat.  caseus,  "cheese."]  The  curd  separated 
from  miUc  by  the  addition  of  rennet,  constituting  the  basis  of 
cheese. 

Cataly'zer.  [From  the  Gr.  kata,  "  down,"  and  luein,  to  "  loose."]  A  sub- 
stance which  hastens  chemical  reactions,  but  does  not  enter  into  the 
reactions.     Enzymes  are  described  as  catalyzers. 

Caud'a  Equi'na.  [Lat.  "  Horse-tail."]  A  term  applied  to  the  termina- 
tion of  the  spinal  cord,  which  gives  off  a  large  number  of  nerves 
which,  when  unravelled,  resemble  a  horse's  tail. 

Cau'date.     [From  the  Lat.  Cauda,  a  "  tail."]     Tail-like. 

Centrifugal.  [From  the  Lat.  centrum,  the  "  centre,"  and  fugere,  "  flee."] 
Flying  off  or  proceeding  from  the  centre. 

Centrip'etal.  [From  the  Lat.  centrum,  the  "  centre,"  and  petere,  "  seek, 
move  toward."]  Tending  or  moving  toward  the  centre.  Opposed 
to  centrifugal. 

Cen'trosome.  [From  the  Gr.  kentron,  "  centre,"  and  soma,  the  "  body."] 
A  pecuUar  rounded  body  lying  near  the  nucleus  of  the  cell.  It  is 
regarded  as  the  dynamic  element  by  means  of  which  the  machinery 
of  cell  division  is  organized. 

Cerebel'lum.  [Dim.  of  Lat.  cerebrum,  the  "  brain."]  The  hinder  and 
lower  part  of  the  brain ;  the  little  brain. 

Cer'ebrum.     [Lat.  the  "  brain."]     Chief  portion  of  brain. 


476  GLOSSARY 

Ceru'minous.  [From  the  Lat.  cerumen,  "  ear-wax."]  A  term  applied 
to  the  glands  secreting  cerumen,  ear-wax. 

Cer'vix.  [Lat.]  The  neck  (httle  used).  Part  of  an  organ  Ukened  to 
a  neck. 

Choles'terin.     [From  the  Gr.  chole,  "  bile,"  and  stear,  "  fat."]    A  taste- 
less, inodorous,  fatty  substance  found  in  small  quantities  in  the  pro 
toplasm  of  all  cells,  especially  in  nerve  tissue,  blood  corpuscles,  and 
bile.    Its  origin  and  function  are  not  known. 

Chon'drin.  [From  the  Gr.  chondros,  "  cartilage."]  A  kind  of  gelatine 
obtained  by  boihng  cartilage. 

Chor'da  Tym'pani.  [Lat.]  The  tympanic  cord,  a  branch  of  the  facial, 
or  seventh  cranial,  nerve  which  traverses  the  tympanic  cavity  and 
joins  the  gustatory,  or  lingual,  nerve. 

Chor'dae  Tendin'eae.     [Lat.]     Tendinous  cords. 

Cho'roid.  [From  the  Gr.  chorion,  "  skin,"  and  eidos,  "  form,"  or  "  re- 
semblance."] A  skin-like  membrane;  the  second  coat  of  the 
eye. 

Chyle.  [From  the  Gr.  chidos,  "  juice."]  Milky  fluid  of  intestinal  diges- 
tion, found  in  the  lymphatics  of  the  intestines. 

Chyme.  [From  the  Gr.  chumos,  "  juice."]  Food  that  has  undergone 
gastric  but  not  intestinal  digestion.  (Both  chyle  and  ch3Tne  signify 
literally  liquid,  or  juice.) 

Cica'trix.  [Lat.  a  "  scar."]  The  mark,  or  scar,  left  after  the  healing  of 
a  wound. 

Cil'ia.     [Lat.  the  "  eyelashes."]    Hair-like  processes  of  certain  cells. 

Circumval'late.  [From  the  Lat.  circumvallo,  to  "  surround  with  a  wall."] 
Surrounded  by  a  icall. 

Clav'icle.  [From  the.  dim.  of  Lat.  clavis,  a  "  key."]  The  collar-bone, 
so  named  from  its  shape. 

Coagula'tion.  [From  the  Lat.  coag'ulo,  to  "  curdle."]  Applied  to  the 
process  by  which  the  blood  clots  or  solidifies. 

Coalesce'.  [From  the  Lat.  con,  "  together,"  and  alere,  to  "  nourish."] 
To  grow  together. 

Coc'cyx.  [Lat.  the  "  cuckoo."]  The  lower  curved  bone  of  the  spine, 
resembling  a  cuckoo's  bill  in  shape. 

Coch'lea.  [Lat.  a  "  snail,"  a  "  snail-shell  " ;  hence,  anything  spiral.] 
A  term  appUed  to  a  cavity  of  the  internal  ear. 

Coe'Uac.  [From  the  Gr.  koilos,  "  hollow."]  Pertaining  to  the  abdominal 
cavity. 


GLOSSARY  477 

CoUat'erals.  [From  the  Lat.  con,  "  together,"  and  lateralis,  "  of  the  side."] 
Situated  at  the  side ;  hence,  also  secondary. 

Co'lon.  [Gr.  kolon.]  That  portion  of  the  large  intestine  which  extends 
from  the  caecum  to  the  rectum. 

Colum'nae  Car'neae.  [Lat.]  "  Fleshy  columns  " ;  muscular  projections 
in  the  ventricles  of  the  heart. 

Com'missure.  [From  the  Lat.  con,  "  together,"  and  njitto,  missum,  to 
"  send."]  A  joining  or  uniting  together.  Something  which  joins 
together. 

Con'cave.  [From  the  Lat.  con,  "  together,"  and  cavus,  a  "  hollow."]  The 
interior  of  a  curved  surface. 

Con'cha.  [Lat.  a  "  shell."]  A  term  applied  to  the  hollow  portion  of 
the  external  ear. 

Con'dyloid.  [From  the  Gr.  kondulos,  a  "  knob,"  or  "  knuckle,"  and 
eidos,  "  hkeness."]  A  term  applied  to  joints  and  processes  of  bone 
having  flattened  knobs  or  heads. 

Congen'ital.  [From  the  Lat.  con,  "  together,"  and  gignere,  to  "  beget."] 
Existing  from  birth. 

Conjuncti'va.  [From  the  Lat.  con,  "  together,"  and  jungo,  junctum,  to 
"  join."]  A  term  appUed  to  the  delicate  mucous  membrane  which 
lines  both  eyeUds  and  covers  the  external  portion  of  the  eyeball. 

Contig'uous.  [From  the  Lat.  contiguus,  akin  to  contingere,  "  to  touch  on 
all  sides."]     Adjacent;   near;   in  actual  contact. 

Convec'tion.  [From  the  Lat.  con,  "together,"  and  vehere,  to  "  carry."]  A 
process  of  transfer  or  transmission  as  of  heat  or  electricity.  The 
term  "  convection  currents  "  is  used  in  the  text,  and  appUes  to  cur- 
rents of  air  produced  by  differences  in  temperature  and  density. 
Warm  air  expands,  becomes  less  dense,  and  is  forced  upward  by  the 
cooler  air,  which  is  heavier  and  sinks  down.  In  this  way  convection 
currents  are  established. 

Converge'.  [From  the  Lat.  con,  "  together,"  vergere,  to  "  inchne."]  To 
join  at  a  point. 

Con'vex.  [From  the  Lat.  convexus,  "  vaulted."]  The  exterior  of  a  curved 
surface. 

Convolu'tions.  [From  the  Lat.  con,  and  vol'vo,  to  "  roU  together."]  The 
tortuous  foldings  of  the  external  surface  of  the  brain. 

Cor'acoid.  [From  the  Gr.  korakos,  a  "  crow,"  and  eidos,  "  form."]  Pro- 
cess of  the  scapula,  so  named  because  it  was  thought  to  be  the  shape 
of  a  crow's  beak. 


478  GLOSSARY 

Co'rium.     [Lat.  the  "  skin."]    The  deep  layer  of  the  skin ;  the  derma. 
Cor'nea.     [From  the  Lat.  cormi,  a  "  horn."]     The  transparent  anterioi 

portion  of  the  eyeball. 
Cor'onary.     [From  the  Lat.  corona,  a  "  crown."]    A  term  apphed  to 

vessels,  ligaments,  and  nerves  which  encircle  parts  like  a  crown,  as 

the  coronary  arteries  of  the  heart. 
Cor'pora  Aran'tii.     [From  the  Lat.  corpus,  the  "  body."]     Fibro-cartilagi- 

nous  nodules  situated  one  in  the  centre  of  the  free  edge  of  each  of 

the  segments  of  the  aortic  and  pulmonary  valves.    Named  from 

Aranzi,  an  ItaUan  anatomist. 
Cor'pus   Callo'sum.     [Lat.]     "  Callous  body,"   or  substance.     A  name 

given  to  the  hard  substance  uniting  the  cerebral  hemispheres. 
Cor'tex.     [Lat.  "  bark."]     External  or  surface  layer  of  an  organ,  such 

as  the  kidney  or  brain. 
Cos'tal.     [From  the  Lat.  costa,  a  "  rib."]     Pertaining  to  the  ribs. 
Cox'a,  pi.  Coxae.     [From  the  Lat.  coxa,  "  hip."]     The  hip  bone,  os  coxae 

or  OS  innominatum. 
Crena'ted.      [From   the    Lat.    crena,    a    "  notch."]      Notched    on    the 

edge. 
Crib'riform.     [From  the  Lat.  cribrum,  a  "  sieve,"  and  forma,  "  form."] 

Perforated  like  a  sieve. 
Cri'coid.     [From  the  Gr.  kri'kos,  a  "  ring."]    A  cartilage  of  the  larynx 

resembling  a  seal-ring  in  shape. 
Cru'ra  Cer'ebri.     [From  the  Lat.  crxis  (pi.  crura),  a  "  leg."]     Legs,  or 

pillars,  of  the  cerebrum. 
Crypt.     [From  the  Gr.  knjpto,  to  "  liide."]     A  secreting  cainty ;  a  folUcle, 

or  glandular  cavity. 
Cune'iform.     [From  the  Lat.  cunetis,  a  "  wedge,"  and  forma,  "  shape."] 

Having  the  shape  or  form  of  a  wedge.     Name  given  to  two  carpal 

and  six  tarsal  bones. 
Cu'ticle.     [From  the  dim.  of  Lat.  cutis,  the  "  skin."]    A  term  apphed  to 

the  upper,  or  epiclormal,  layer  of  the  skin. 
Cu'tis  Ve'ra.     [Lat.]     The  true  skin;    that  underneath  the  epidermal 

layer. 
Cys'tic.     [From  the  Gr.  kustis,  the  "  bladder."]     Pertaining  to  a  cyst,  — 

a  bladder  or  sac. 
Cy'toplasm.     [From  the  Gr.  kidos,  a  "  cell,"  and  plasso,  to  "  form."] 

The  name  given  by  Kolliker  to  the  contents  of  a  cell;  same  as  pro- 
toplasm. 


GLOSSARY  479 

Decid'uous.     [From  the  Lat.  deciduus,  "  that  falls  down."]     FaUing  or 

liable  to  fall.     Not  permanent. 
Decussa'tion.     [From   the    Lat.  decusso,  decussaium,  to   "  cross."]     To 

cross  in  the  form  of  the  letter  X. 
Degluti'tion.     [From  the  Lat.   de,   "  down,"  and  gliditio,   "  swallow."] 

The  act  or  power  of  swallowing. 
Del'toid.    Ha\ang  a  triangular  shape ;  resembling  the  Greek  letter  A(deUa) . 
Den'drite.     [From  the  Gr.  dendrites,  "  pertaining  to  a  tree."]     The  name 

given  to  the  branching  processes  of  the  neurone  wliich  begin  to 

divide  and  subdivide  as  soon  as  they  leave  the  nerve-cell. 
Denti'tion.     [From  the  Lat.  dentitio,  "  teetliing."] 

L   The  process  of  cutting  teeth. 

2.  The  time  during  wliich  teeth  are  being  cut. 

3.  The  kind,  number,  and  arrangement  of  teeth  proper  to  any  animal. 
Diabe'tes  Mel'litus.     [From  the  Gr.  dia,  "  through,"  baino,  to  "  go,"  and 

Lat.  mel,  "  honey."]     Excessive  flow  of  sugar-containing  urine. 
Diapede'sis.     [From  the  Gr.  dia,  "  through,"  and  pedad,  to  "  leap,"  to 

"  go."]     Passing  of  the  red  blood-corpuscles  through  vessel  walls 

without  rupture. 
Di'aphragm.     [From  the  Gr.  diaphrasso,  to  "  divide  in  the  middle  by  a 

partition."]     The  partition  muscle  dividing  the  cavity  of  the  chest 

from  that  of  the  abdomen. 
Diarthro'sis.     [From  the  Gr.  dia,  "  through,"  as  implying  no  impediment, 

and  arthron,  a  "  joint."]     A  freely  movable  articulation. 
Di'astase.     [From  the  Gr.  diastasis,  "  separate."]    An  enzyme   of  the 

saliva  and  pancreatic  juice  capable  of  decomposing  carbohydrates. 
Dias'tole.     [From  the  Gr.  diastello,  to  "  dilate."]     The  dilatation  of  the 

heart. 
Diath'esis.     [From  the  Gr.  dia,   "  through,"  and  tithenai,  to  "  place."] 

A  congenital  condition  of  the  system  which  renders  it  peculiarly 

liable  to  some  diseases. 
Dichot'omous.     [From  the  Gr.  dichotomos,  "  cutting  in  two."]     Pertaining 

to  or  consisting  of  a  pair  or  pairs.     Divided  into  two. 
Diges'tion.     [From  the  Lat.  digestio,  "  arrangement."]     The  process  of 

converting  the  food  from  the  state  in  which  it  enters  the  mouth  to 

that  in  which  it  can  pass  from  the  alimentary  canal  into  the  blood- 
vessels and  lymphatics. 
Dip'loe.     [From  the  Gr.  diploo,  to  "  double,"  to  "  fold."]     The  osseous 

tissue  between  the  tables  of  the  skull. 


480  GLOSSARY 

Disac'charid.      [From  the  Lat.  (lis,  "  twice,"  and  saccharon,  "  sugar."\ 

A  complex  sugar  which  on  hydrolysis  yields  two  molecules  of  a 

simple  sugar. 

Disaccharid  Glucose       Fructose 

CnH^jOn  +  HoO^CeHnOe  +  CeHiA 
Dis'cus  Prolig'erus,  or  germ  disk.    A  term  appUed  to  a  mass  of  cells 

clinging  to  the  ovum  when  it  is  set  free  from  the  ovary.    More  recent 

term  is  "  ovarian  mound." 
Disintegra'tion.     [From   the    Lat.  dis,    "  twice,"    and    integer,  "  entire, 

wliolc."]    A  breaking  apart. 
Distilla'tion.     [From  the  Lat.  distillatio,  a  "  dripping  down."]     The  act 

of  distilling  or  of  falling  in  drops.     The  operation  of  drixing  off  gas  or 

vapor  from  volatile  liquids  or  solids,  by  heat  in  a  retort  or  still,  and 

the  condensation  of  the  products  as  far  as  possible  by  a  cool  receiver. 
Dor'sal.     [From  the  Lat.  dorsum,  the  "  back."]    Pertaining  to  the  back, 

or  posterior  part,  of  an  organ. 
Duode'num.     [From   the   Lat.    duodeni,    "  twelve   each."]     First  part 

of  small  intestines,  so  called  because  about  twelve  fingers'  breadth 

in  length. 
Du'ra  Ma'ter.     [Lat.]    The  "  hard  mother,"  called  dura  because  of  its 

great  resistance,  and  mater  because  it  is  the  guardian  or  protector 

of  the  brain.     The  outer  membrane  of  the  brain  and  spinal  cord. 
Dyspnce'a.     [From  the  Gr.  dys,  "  difficult,"  and  pneo,  to  "  breathe."] 

Difficult  breathing. 

Ec'toderm.  [From  the  Gr.  ektos,  "  outside,"  and  denna,  the  "  skin."] 
The  completed  outer  layer  of  cells,  or  outer  blastodermic  membrane. 
Same  as  epiblast. 

Ectop'ic.  [From  the  Gr.  ek,  "  out  of,"  and  topos,  "  place."]  Characterized 
by  being  out  of  place. 

Efferent.  [From  the  Lat.  ex,  "  out,"  and  fero,  to  "  carry."]  Bearing 
or  carrying  outwards,  as  from  the  centre  to  the  periphery. 

Elemen'tary.     Pertaining  to  or  of  the  nature  of  an  element  or  elements. 

Elimina'tion.  [From  the  Lat.  e,  "out  of,"  and  lirmn,  liminis,  a  "  thresh- 
old."] The  act  of  expelling  waste  matters.  EUminate  signifies, 
literally,  to  throw  out  of  doors. 

Em'bolus.  [From  the  Gr.  embolos,  a  wedge.]  A  portion  of  a  blood  clot 
which  has  been  formed  in  one  of  the  larger  vessels,  and  has  afterward 
been  forced  into  one  of  the  smaller  vessels  where  it  may  act  as  a 
wedge. 


GLOSSARY  481 

Em'bryo.    The  ovum  and  product  of  conception  up  to  the  fourth  month, 

when  it  becomes  known  as  the  foetus. 
Emul'sion.     [From  the  Lat.  emulgere,  to  "  milk."]    A  mixture  of  liquids, 

insoluble  in  one  another,  where  one  is  suspended  in  the  other  in  the 

form  of  minute  globules,  as  the  fat  in  milk. 
Enarthro'sis.     [From  the  Gr.  en,  "  in,"  and  arthron,  a  "  joint."]    An 

articulation  in  which  the  head  of  one  bone  is  received  into  the  cavity 

of  another,  and  can  be  moved  in  all  directions. 
Endocar'dium.     [From  the  Gr.  endon,  "  within,"  and  kardia,  "  heart."] 

Lining  of  the  heart.  . 
En'dolymph.     [From  the  Gr.  endon,  "  within,"  and  Lat.  lympha,  "  water."] 

The  fluid  in  the  membranous  labyrinth  of  the  ear. 
Endos'teum.     [From  the  Gr.  endon,  "  within,"  and  osteon,  a  "  bone."] 

The  lining  membrane  of  the  medullary  cavity  of  a  bone ;  the  internal 

periosteum. 
Endothe'lium.     [From  the  Gr.  endon,  "  within,"  and  thele,  the  "  nipple."] 

A  term  appUed  to  single  layers  of  flattened  transparent  cells,  applied 

to  each  other  at  their  edges  and  Uning  certain  surfaces  and  cavities 

of  the  body.     In  contradistinction  to  epithelium. 
En'siform.     [From  the  Lat.   ensis,   a   "sword,"   and  forma,   "form."] 

Shaped  like  a  sword. 
En'toderm.     [From  the  Gr.  endon,  "  within,"  and  derma,  the  "  skin."] 

The  completed  inner  layer  of  cells,  or  inner  blastodermic  membrane. 

Opposed  to  ectoderm.     Same  as  hypoblast. 
En'zyme.     [From  the  Gr.  en,  "  in,"  and  zume,  "  leaven."]    A  term  applied 

to  a  class  of  ferments. 
Ep'iblast.      [From  the    Gr.   epi,    "  upon,"   and  blastos,  a   "  germ,"   or 

"  sprout."]      The  external,  or  upper,  layer  of  the  germinal  mem- 
brane. 
Epicra'nial.     [From  the  Gr.  epi,  "  upon,"  and  kranion,  "the  cranium."] 

That  which  is  upon  the  cranium  or  scalp. 
Epider'mis.     [From  the  Gr.  epi,  "  upon,"  and  derma,  the  "  skin."]     The 

outer  layer  of  the  skin. 
Epigas'tric.     [From    the    Gr.   epi,    "  upon,"    and  gaster,    "  stomach."] 

Lying  upon,  distributed  over,  or  pertaining  to  the  abdomen  or  the 

stomach. 
Epiglot'tis.     [From  the  Gr.  epi,  "  upon,"  and  glottis,  the  "  glottis."]    The 

cartilage  at  the  root  of  the  tongue  which  forms  a  Ud  or  cover  for  the 

aperture  of  the  larnyx. 
2i 


482  GLOSSARY 

Epimys'ium.  [From  the  Gr.  epi,  "  upon,"  and  miis,  "  muscle."]  The 
slicath  of  connective  tissue  surrounding  an  entire  muscle. 

Epistro'pheus.  [From  the  Gr.  epi,  "  upon,"  and  strephein,  "  turn."]  The 
second  cervical  or  odontoid  vertebra;  the  axis;  so  called  because 
the  atlas  turns  upon  it. 

Epithe'lial.  [From  the  Gr.  epi,  "  upon,"  and  thele,  the  "  nipple."]  Per- 
taining to  the  epithelium,  the  cuticle  covering  the  nipple,  or  any 
mucous  membrane.  The  term  epithelium  is  now  appUed  to  the 
tissue  composed  of  cells  covering  or  hning  all  surfaces  of  the  body. 

Eryth'rocyte.  [From  the  Gr.  eruthros,  "red,"  and  kutos,  a  "cell."]  A 
fully  developed  red  blood-corpuscle. 

Eth'moid.  [From  the  Gr.  ethmos,  a  "  sieve,"  and  eidos,  "  form,"  "  re- 
semblance."] Sieve-like.  A  bone  of  the  cranium,  part  of  which 
is  pierced  by  a  number  of  holes. 

Evapora'tion.  [From  the  Lat.  e,  "  out,"  and  vapor,  "  steam."]  The  act 
of  resolving  into  vapor.  In  order  to  produce  vapor,  heat  is  necessary, 
and  if  not  supphed,  is  taken  from  near  objects.  Thus  the  heat  neces- 
sary for  the  evaporation  of  perspiration  is  taken  from  the  body. 

Excre'tion.  [From  the  Lat.  excer'no,  to  "  separate."]  The  separation 
from  the  blood  of  the  waste  particles  of  the  body ;  also  the  materials 
excreted. 

Expira'tion.  [From  the  Lat.  expi'ro,  to  "  breathe  out."]  The  act  of 
forcing  air  out  of  the  lungs. 

Fac'et.     [From  the  Lat.  fades,  "  face."]    A  small,  flat,  articular  surface.] 
Fal'ciform.     [From   the    Lat.  falx,  a   "  sickle,"   and   forma,   "  shape." 

Sickle-shaped. 
Fallo'pian.     A  term  apphed  to  tubes  and  hgaments  first  pointed  out  by 

the  anatomist  Fallopiics. 
Fascic'tilus,   pi.   Fasciculi.     [Lat.  a   "bundle."]     A  bundle  of  close-set 

fibres. 
Fau'ces.     [Lat.,  pi.  of  faux,  fauds,  the  "  throat."]    The  cavity  at  the 

back  of  the  mouth  from  which  the  larynx  and  pharynx  proceed. 
Fecunda'tion.     [From  the  Lat.  fecundatio,  "  impregnation."]     The  act  of 

making  fruitful  or  prolific.     Impregnation. 
Fenes'tra.     [Lat.]    A  window. 
Fermenta'tion.     [From  the  Lat.  fermentum,  "  ferment " ;  perhaps  from 

fervere,   "  to  boil."]    The  process   of   undergoing   an   effervescent 

change  as  by  the  action  of  yeast.    In  physiology  it  refers  to  the 


GLOSSARY  483 

transformation  of  an  organic  substance  into  new  compounds  by  the 
action  of  a  ferment. 

Fibril'la,  pi    Fibril'lae.     [Dim.  of  Lat.  fibra,  a  "  fibre."]    A  little  fibre. 

Fibrin'ogen.     A  protein  in  blood  plasma,  the  main  constituent  of  fibrin. 

Fi'brous.  [From  the  Lat.  fibra,  "  fibre."]  Containing  or  consisting 
of  fibres.     Having  the  character  of  fibres. 

Fib'ula.     [Lat.  a  "  clasp."]     The  long  sphnter  bone  of  the  leg. 

Fil'ifonn.  [From  the  Lat.  filum,  a  "thread,"  and  forma,  "form."] 
Thread-like. 

Fim'briae.     [Lat.  a  "  fringe."]    A  border,  or  fringe. 

Fis'sion.  [From  the  Lat.  findo,  fissum,  to  "  cleave."]  A  cleaving,  or 
breaking  up  into  two  parts. 

Fo'cus.  [From  the  Lat.  focus,  "  hearth  or  fireplace."]  A  po^'nt  at  which 
the  rays  of  light  meet,  after  being  reflected  or  refracted.  Point 
at  which  an  image  is  formed. 

Foe'tus.     The  child  in  utero  from  the  fifth  month  of  pregnancy  till  birth. 

Fol'licle.  [From  the  dim.  of  Lat.  follis,  a  "  bag."]  A  little  bag;  a  small 
gland. 

Fontanelle'.  [Fr.]  A  httle  fountain.  A  term  appUed  to  the  mem- 
branous spaces  between  the  cranial  bones  in  the  new-born  infant, 
in  which  the  pulsation  of  the  blood  in  the  cranial  arteries  was  im- 
agined to  rise  and  fall  like  the  water  in  a  fountain. 

Fora'men,  pi.  Foram'ina.     [Lat.]     An  opening,  hole,  or  aperture. 

Fos'sa,  pi.  Fos'sae.  [From  the  Lat.  fodio,  fossum,  to  "  dig."]  A  depres- 
sion, or  sinus ;  literally,  a  ditch. 

Fo'vea  Centralis.  [Lat.]  Central  depression  of  the  macula  lutea.  The 
point  of  most  acute  vision. 

Fun'giform.  [From  the  Lat.  fungus,  a  "  mushroom,"  Sind forma,  *'  form."] 
Having  the  shape  of  a  mushroom. 

Funic'ulus,  pi.  Funic'uli.  [Dim.  of  Lat.  funis,  a  "  rope."]  A  little  cord, 
or  bundle,  of  aggregated  fibres. 

Fu'siform.  [From  the  Lat.  fusiis,  a  "  spindle,"  and  forma,  "  form."] 
Spindle-shaped. 

Gang'lia,  pi.  of  Gang'lion.  [From  the  Gr.  gagglion,  a  "  knot."]  A 
collection  of  nerve-cells  in  the  course  of  a  nerve  that  has  the  ap- 
pearance of  a  knot. 

Gas'tric.  [From  the  Gr.  gaster,  the  "  stomach."]  Pertaining  to  the 
stomach. 


484  GLOSSARY 

Gastrocne'mius.  [From  the  Gr.  gaster,  the  "  belly,"  and  kneme,  the 
"  leg."]     The  belly-shstped  muscle  of  the  leg. 

Gas'tro-pul'monary.  Same  as  gastro-pneumonic.  [From  the  Gr.  gaster, 
"stomach,"  and  pnevmoji,  a  "lung":  Lat.  pulmo,  a  "lung."] 
Pertaining  to  the  stomach  and  the  lungs*:  applied  to  the  continuous 
mucous  membrane  of  the  respiratory  and  digestive  tracts. 

Gen'erative.  [From  the  Lat.  generare,  to  "  beget."]  Pertaining  to 
generation,  or  propagation.  Connected  with  or  resulting  from  the 
process  of  begetting. 

Genioglos'sus.  [From  the  Gr.  geneion,  the  "  chin,"  and  glossa,  the 
"  tongue."]    A  muscle  connected  with  the  chin  and  tongue. 

Gen'itals.  [From  the  Lat.  genitalis,  "  of  or  belonging  to  generation."] 
Pertaining  to  the  organs  of  generation. 

Gesta'tion.  [From  the  Lat.  gestare,  "  carry,  bear."]  The  act  or  condition 
of  carrying  young  in  the  womb  from  conception  to  delivery.  Preg- 
nancy. 

Ging'lymus.     [From  the  Gr.  gigglunios,  a  "  hinge."]     A  hi7i^e-]omt. 

Gladiolus.  [Dim.  of  Lat.  gladiiis,  a  "  sword."]  The  middle  piece  of  the 
sternum. 

Glair'y.  [From  the  Lat.  clarws,  "  clear  "  ;  Fr.  clair.]  Like  the  clear  white 
part  of  an  egg. 

Gland.  [From  the  Lat.  glans,  an  "  acorn."]  A  secreting  organ.  An 
organ  that  abstracts  certain  materials  from  the  blood  and  makes  of 
them  a  new  substance. 

Gle'noid.  [From  the  Gr.  glene,  a  "  cavity,"  and  eidos,  "  form,"  "  resem- 
blance."]    A  name  given  to  a  shallow  cavity. 

Glob'ulins.  [From  the  Lat.  globus,  perhaps  akin  to  glomus,  "  a  ball."] 
Protein  substances  somewhat  similar  to  the  albumins,  but  differing 
in  their  solubility. 

Glomer'ulus.  [Dim.  of  Lat.  glojyius,  a  "  ball."]  A  botanical  term  signi- 
fying a  small,  dense,  roundish  cluster :  a  term  appUed  to  the  ball- 
like tuft  of  vessels  in  cortical  portion  of  the  kidneys. 

Glos'sopharynge'al.  [From  the  Gr.  glossa,  the  "  tongue,"  and  pharygx, 
the  "  pharynx."]     Belonging  to  the  tongue  and  pharynx. 

Glot'tis.     [Gr.  the  "  mouthpiece  of  a  flute."]     The  aperture  oi  the  lar^mx. 

Glute'i,  pi.  of  Glute'us.  [From  the  Gr.  gloutoi,  the  "  buttocks."]  The 
muscles  forming  the  buttocks. 

Graafian  Fol'licles,  or  Ves'icles.  A  term  appUed  to  the  sacs  in  the 
ovaries,  which  contain  the  ova  or  ceUs. 


GLOSSARY  485 

Granula'tions.  [From  the  Lat.  granulum,  diminutive  of  granum, 
"  grain."]  Grain-like,  fleshy  bodies  that  form  on  the  surface  of 
wounds    and    ulcers. 

Gus'tatory.  [From  the  La,t.  gusto,  gustatum,  to  "taste."]  Belonging  to 
the  sense  of  taste. 

Haemoglo'bin.  [From  the  Gr.  haima,  "  blood,"  and  Lat.  globus,  a 
"  globe,"  or  "  globule."]  A  compound  protein  found  in  the  red 
corpuscles  of  the  blood ;  its  molecules  consist  of  a  protein  portion 
and  of  a  pigment  portion,  the  latter  containing  one  atom  of  iron. 

Haemorrhoi'dal.  [From  the  Gr.  haima,  "  blood,"  and  rhed,  to  "  flow."] 
Pertaining  to  haemorrhoids,  small  tumors  of  the  rectum,  which 
frequently  bleed. 

Haver'sian  Canals.  Canals  in  the  bone,  so  called  from  their  discoverer, 
Dr.  Clopton  Havers. 

Hemophil'ia.  [From  the  Gr.  haivia,  "  blood,"  and  philein,  "  to  love."]  A 
congenital,  morbid  condition,  characterized  by  a  tendency  to  bleed 
immoderately  from  any  insignificant  wound,  or  even  spontaneously. 

Hepat'ic.     [From  the  Gr.  hepar,  the  "  liver."]     Pertaining  to  the  liver. 

Hi'lum,  sometimes  UTitten  Hi'lus.  [Lat.]  It  is  the  depression  (usually 
on  concave  side)  of  a  gland,  where  vessels,  nerves,  and  ducts  enter 
or  leave. 

Histol'ogy.  [From  the  Gr.  histos,  a  "  web,  tissue,"  and  logos,  "  word."] 
That  branch  of  anatomy  which  is  concerned  with  the  structure, 
especially  the  microscopic  structure,  of  the  tissues  of  the  body. 

Homoge'neous.  [From  the  Gr.  homos,  "  the  same,"  and  genos,  "  kind."] 
Of  the  same  kind  or  quality  throughout ;  uniform  in  nature,  —  the 
reverse  of  heterogeneous. 

Hor'mone.  [From  the  Gr.  hormao,  "  to  set  in  motion."]  A  chemical 
substance  which  is  produced  in  one  organ,  and  on  being  carried  by  the 
blood  to  another  organ,  stimulates  this  latter  to  functional  activity. 

Hu'merus.  [Lat.  the  "  shoulder."]  The  arm-bone  which  concurs  in 
forming  the  shoulder. 

Hy'aline.  [From  the  Gr.  hyalos,  "  glass."]  Glass-like,  resembhng  glass 
in  transparency. 

Hy'aloid.  [From  the  Gr.  hyalos,  "  glass,"  and  eidos,  "  form."']  The 
name  given  the  membrane  which  encloses  the  vitreous  humor  of 
the  eye.  It  invests  the  vitreous  humor  except  in  front,  where  it 
is  continuous  with  the  suspensory  ligament  of  the  crystalUne  lens. 


486  GLOSSARY 

Hydrotherapy.  [From  the  Gr.  hudor,  "  water,"  and  therapeuein,  to 
"  heal."]  A  mode  of  treating  disease  by  the  copious  use  of  pure 
water,  both  internallj'  and  externally. 

Hy'oid.  [From  the  Gr.  letter  upsilon,  v,  and  eidos,  "  form,"  "  resem- 
blance."] The  bone  at  the  root  of  the  tongue,  shaped  Uke  the 
Greek  lett^'r  upsilon,  v. 

Hypermetro'pia.  [From  the  Gr.  hyper,  "  over,"  "  beyond,"  metron, 
"  measure,"  and  dps,  the  "  eye."]    Far-sightedness. 

Hyperpnoe'a.  [From  the  Gr.  hyper,  "over,"  and  pneo,  to  "breathe."] 
Energetic  or  labored  respiration. 

Hyper'trophy.  [From  the  Gr.  hyper,  "  over,"  and  trophi,  "  nourish- 
ment."] Excessive  growth ;  thickening  or  enlargement  of  any  part 
or  organ. 

Hy'poblast.  [From  the  Gr.  hypo,  "  under,"  and  blastos,  a  "  sprout,"  or 
"  germ."]     The  internal,  or  under,  laj'er  of  the  germinal  membrane. 

Hypochon'driac.  [From  the  Gr.  hypo,  "  under,"  and  chondros,  a  "  carti- 
lage."] A  term  apphed  to  the  region  of  the  abdomen  under  the  car- 
tilages of  the  false  ribs. 

Hypogas'tric.  [From  the  Gr.  hypo,  "  under,"  and  gaster,  "  stomach."] 
Situated  below  the  stomach.     Pertaining  to  the  hjTDOgastrium. 

Hypoglos'sal.  [From  the  Gr.  hypo,  "  under,"  and  glossa,  the  "  tongue."] 
A  name  given  to  the  motor  nerve  of  the  tongue. 

Hypoph'ysis.  [From  the  Gr.  hypo,  "under,"  and  phusis,  a  "growing."] 
Tlie  pituitary  body  of  the  brain  which  is  lodged  in  the  central  de- 
pression of  the  sphenoid  bone. 

Il'eum.     [From  the  Gr.  eileo,  to  "  twist."]     The  twisted  portion  of  the 

small  intestine. 
H'ium,  pi.  Il'ia.     [From the  Lat.  ilium,  the"  flank."]     The  upper  part  of 

the  OS  innominatum. 
Inci'sor.     [From  the  Lat.  inci'so,  to  "  cut."]     Apphed  to  the  front  teeth 

of  both  jaws,  which  have  sharp  cutting  edges. 
In'cus.     [Lat.]     An  anx-il ;   the  name  of  one  of  the  bones  of  the  middle 

ear. 
Inflamma'tion.     [From  the  Lat.  inflammatio,  a  "  setting  on  fire."]    A 

morbid  condition  characterized  by  pain,   heat,   redness,  sweUing, 

and  usually  loss  of  function. 
Infundib'ula.     [Lat.  pi.  of  infundibulum,  a  "  funnel."]    Funnel-sh&ped 

canals. 


GLOSSARY  487 

Ingest'.     [From  the  Lat.  in,  "in,"  and  gerere,  to  "  bear."]     Taking  food 

into  the  stomach. 
In'guinal.     [From  the  Lat.  inguen,  the  "  groin."]     Pertaining  to  the  groin. 
Inhibi'tion.     [From  the  Lat.  inhibere,  "  restrain."]     The  lowering  of  the 

action  of  a  nervous  mechanism  by  nervous  impulses  reaching  it  from 

a  connected  mechanism. 
Innom'inate.     [From  the  Lat.  innominatus,  "  nameless."]    A  name  given 

an  artery,  vein,  and  a  bone. 
Inoc'ulate.     [From  the  Lat.  in,  "in,"  and  oculus,  "bud."]    The  insertion 

of  virus  into  a  wound  or  abrasion  for  the  purpose  of  communicating 

a  disease. 
Inos'culate.     [From  the  Lat.  in,  "  into,"  and  osculum,  a  "  Uttle  mouth."] 

To  unite,  to  open  into  each  other. 
In'sulate.     [From  the  Lat.  insula,  an  "  island."]     To  isolate  or  separate 

from  surroundings. 
Integ'ument.     [From  the  Lat.  in,  and  te'go,  to  "  cover."]    The  skin,  or 

outer  covering  of  the  body. 
Intercel'lular.     Lying  between  cells. 

Intercos'tal.  [From  the  Lat.  inter,  "  between,"  and  costa,  "  rib."]  Situ- 
ated or  intervening  between  successive  ribs  of  the  same  side  of  the 

body. 
Interlob'ular.     That  which  Ues  between  the  lobules  of  any  organ. 
Inter'stice.     [From  the  Lat.  inter,  "  between,"  and  sto,  or  sisto,  to  "stand."] 

The  space  which  stands  between  tilings ;  spaces  between  parts. 
Intersti'tial.     Pertaining  to  or  containing  interstices. 
Intes'tine.     [From  the  Lat.  in'tus,  "  within."]    The  part  of  the  alimentary 

canal  which  is  continuous  with  the  lower  end  of  the  stomach ;   also 

called  the  bowels. 
Intralob'ular.     That  which  lies  within  the  lobules  of  any  organ. 
I'ris.     [Lat.  the  "  rainbow."]     The  colored  membrane  suspended  behind 

the  cornea  of  the  eye.     It  receives  its  name  from  the  variety  of  its 

colors. 
Is'chium.     [From  the  Gr.  ischio,  to  "  support."]     The  lower  portion  of  the 

OS  innominatum ;  that  upon  which  the  body  is  supported  in  a  sitting 

posture. 

Jeju'num.  [From  the  Lat.  jejunum,  "  fasting,"  "  empty."]  The  part  of 
the  small  intestine  comprised  between  the  duodenum  and  ileum.  It 
has  been  so  called  because  it  is  almost  always  found  empttj  after  death. 


488  GLOSSARY 

Ju'gular.  [From  the  L&t.  jugulum,  the  "throat."]  Pertaining  to  the 
throat. 

Katabol'ism.  [From  the  Gr.  katabole,  "  a  throwing  down."]  Pertaining 
to  katabolism,  the  process  by  means  of  which  complex  substances 
are  rendered  more  simple  and  less  complex.  The  opposite  of 
anabolism. 

Karyokine'sis.  [From  the  Gr.  karuon,  "  a  nut,"  and  kinein  "to  move."] 
The  indirect  division  of  cells,  in  which  prior  to  the  division  of  the 
cell  protoplasm  complicated  changes  take  place  in  the  nucleus,  at- 
tended with  movement  of  the  nuclear  fil:)rils. 

Lac'rimal.     [From  the  Lat.  lacrima,  "  tear."]     Of  or  pertaining  to  tears. 
Lacta'tion.     [From  the  Lat.  lac,  ladis,  "  milk."]     The  period  of  gi\'ing 

7mlk. 
Lactiferous.     [From  the  Lat.  lac,  "  milk,"  and  ferre,  "  bear."]     Bearing, 

or  conveying,  milk,  as  a  lactiferous  duct. 
Lacu'na,  pi.  Lacu'nse.     [Lat.  a  "  cavity,"  an  "  opening."]     A  httle  hollow 

space. 
Lambdoi'dal.     [From  the  Gr.  letter  A  (Lambda),  and    eidos,    "  fonn," 

"  rosemblanco."]     ResembUng  the  Gr.  letter  A. 
Lamel'la,  pi.  Lamel'lae.     [Lat.]     A  thin  plate,  or  layer. 
Laryn'goscope.     [From  the  Gr.   laryg.v,  the  "  larynx,"  and  skopeo,  to 

"  look  at."]     The  instrument  bj'  which  the  larynx  may  be  examined 

in  the  living  subject. 
Lar'ynx.     The  upper  part  of  the  air-passage,  between  the  trachea  and 

the  base  of  the  tongue. 
Latis'simus  Dor'si.     [Lat.  superlative  of  latus,  "  broad,"  "  wide,"  and 

dorsum,  the  "back."]     The  widest  muscle  of  the  back. 
Lens.      [From    the  Lat.  lem,  "  a  lentil."]      A  transparent    substance, 

ground  ^^^th  two  opposite  regular  surfaces,  either  both  curved,  or  one 

curved  and  one  plane.     There  are  two  general  classes  of  lenses : 

(1)  concave,  which  are  thinner  at  the  centre  than  at  the  edges; 

and  (2)  convex,  which  are  thicker  at  the  centre  than  at  the  edges. 

(See  page  43 L) 
Lip'ase.     [From  the  Gr.  lipos,  "  fat."]    An  enzyme  of  the  pancreatic 

juice,  capable  of  decomposing  fats.     Same  as  steapsin. 
Lob'ule.     [From  the  dim.  of  Lat.  lobus,  a  "  lobe."]    A  stnall  lobe. 
Lum'bar.     [From  the  Lat.   lumbaris,  the  "  loin."]     Pertaining  to  the 

loitis. 


GLOSSARY  489 

Lymph.  [From  the  Lat.  hjmpha,  "  water."]  A  colorless  fluid,  resem- 
bling water  in  appearance. 

Lymph'ocyte.  [From  the  Lat.  lympha,  "water, "  and  Gr.  kutos,  "  a  cell."] 
Name  given  to  recently  formed  white  blood-corpuscles  that  later 
become  leucocytes. 

Lymph'oid.  [From  the  Lat.  lympha,  "  water,"  and  Gr.  eidos,  "  form," 
"  resemblance."]     Having  resemblance  to  lymph. 

Mac'ula  Lute'a.     [Lat.]     Yellow  spot. 

Ma'lar.      [From    the    Lat.    jnala,    the    "  cheek."]     Pertaining   to   the 

cheek. 
Malle'olus,  pi.  Malle'oli.     [Dim.  of  Lat.  malleus,  a  "hammer."]     A  name 

given  to  the  pointed  projections  formed  by  the  bones  of  the  leg  at 

the  ankle-joint. 
Malpigh'ian  Bod'ies.     [So  called  in  honor  of  Malpighi,  a  celebrated  Italian 

anatomist.]    A  term  applied  to  small  bodies,  or  corpuscles,  found  in 

the  kidney  and  spleen. 
Mam'mary.     [From  the  Lat.  mamma,  the  "  breast."]     Of  or  pertain- 
ing to  the  breast. 
Man'dible.     [From    the    Lat.    mandere,    "  chew,"    "  masticate."]     The 

under  jaw,  or  inferior  maxillary,  as  distinguished  from  the  upper 

jaw,  or  superior  maxillary. 
Manu'brium.      [Lat.  a  "  haft,"  a  "  handle."]     Name  given  to  the  upper 

portion  of  the  sternum  or  breast  bone. 
Mas'seter.     [From  the  Gr.  massaomai,  to  "  chew."]     One  of  the  muscles 

of  mastication. 
Mas'toid.     [From  the  Gr.  mastos,  the  "  breast,"  and  eidos,  "  form,"  "  re- 
semblance."]    Shaped  like  the  breast. 
Ma'trix.     [Lat.]     The  womb.     Producing  or  containing  substance. 
Matura'tion.     [From  the  Lat.  maturatio,  a  "  hastening."]     The  process 

of  bringing,  or  of  coming  to  maturity. 
Medul'la  Oblonga'ta.     [Lat.]     The  "  oblong  marrow  "  ;   that  portion  of 

the  brain  which  lies  within  the  skull,  upon  the  basilar  process  of  the 

occipital  bone. 
Meibo'mian.     A  term  appUed  to  the  small  glands  between  the  conjunctiva 

and  tarsal  cartilages,  discovered  by  Meibomitis.     ISIore  recent  term 

is  tarsal  glands. 
Mem'brane.     [From  the  Gr.  membrane,  "  parchment."]    An  enveloping 

or  a  liriing  tissue  of  the  body. 


490  GLOSSARY 

Menin'ges.  [The  pi.  of  Gr.  vienigx,  "  membrane."]  Term  ap- 
plied to  the  three  membranes  that  invest  the  brain  and  spinal 
cord. 

Mes'entery.  [From  the  Gr.  mesos,  "  middle,"  and  enteron,  the  "  in- 
testine."] A  duplicature  of  the  peritoneum  covering  the  small 
intestine,  which  occujiies  the  middle,  or  centre,  of  the  abdominal 
cavity. 

Mes'oblast.  [From  the  Gr.  mesos,  "  middle,"  and  blastos,  a  "  germ  "  or 
"  sprout."]     The  middle  layer  of  the  germinal  membrane. 

Mesoco'lon.     A  dupUcature  of  the  peritoneum  covering  the  colon. 

Mes'oderm.  [From  the  Gr.  mesos,  "  middle,"  and  derma,  the  "  skin." 
The  middle  germinal  layer  of  cells  lying  between  the  ectoderm  and 
entoderm.     Same  as  mesoblast. 

Metab'olism.  [From  the  Gr.  metabole,  "  change."]  The  changes  taking 
place  in  cells,  whereby  they  become  more  complex  and  contain  more 
force,  or  less  complex  and  contain  less  force.  The  former  is  construc- 
tive metabolism,  or  anaboUsm;  the  latter,  destructive  metabolism, 
or  kataboUsm. 

Metacar'pus.  [From  the  Gr.  m£ta,  "  after,"  or  "  beyond,"  and  karpos,  the 
"  wrist."]  The  part  of  the  hand  comprised  between  the  ivrist  and 
fingers. 

Metatar'sus.  [From  the  Gr.  meta,  "  after,"  or  "  beyond,"  and  tarsos,  the 
"  instep."]  That  part  of  the  foot  comprised  between  the  instep  and 
toes. 

Mi'tral.     ResembUng  a  mitre. 

Mo'lar.  [From  the  Lat.  mola,  a  "  mill."]  A  term  applied  to  the  teeth, 
wliich  bruise,  or  grind,  the  food. 

Monosaccharid.  [From  the  Gr.  monos,  "  one,  single,"  and  sakcharis, 
"  sugar."]    A  simple  sugar.     CeHnOs- 

Mo'tor  Oc'uli.     [Lat.]     Mover  of  the  eye. 

Mu'cin,  the  chief  constituent  of  mucus. 

Mus'cle.  [From  the  Gr.  mus,  "  muscle."]  A  kind  of  animal  tissue  con- 
sisting of  bundles  of  fibres  whose  essential  physiological  characteris- 
tic is  contractiUty. 

Myocar'dium.  [From  the  Gr.  mus,  mnos,  a  "  muscle,"  and  kardia,  the 
"  heart."]     The  muscidar  structure  of  the  heart. 

Myo'pia.  [From  the  Gr.  7nu6,  to  "  contract,"  and  dps,  the  "  eye."] 
Nearsightedness. 

My'osin.     Cliief  protein  substance  of  muscle. 


GLOSSARY  491 

Na'ris,  pi.  Na'res.     [Lat.]     A  nostril. 

Neurax'oi^.     [From  the  Gr.  neuron,  "  nerve,"  and  axon.]    An  axis  cylinder 

process. 
Neurilem'ma.     [From  the  Gr.  neuron,  a  "  nerve,"  and  lemma,  a  "  coat,"  or 

"  covering."]     Nerve-sheath. 
Neu'rone.     [From  the  Gr.  neuron,  a  "  nerve."]     The  nerve-cell,  inclusive 

of  all  its  processes. 
Node.     [From  the  Lat.  norfi/s,  a  "  knot."]    A  knot,  or  what  resembles  one. 

A  lymphatic  ganghon. 
Nucle'olus,  pi.  Nucle'oli.     [Dim.  of  Lat.  nucleus,  a  "kernel."]     A  smaller 

nucleus  within  the  nucleus. 
Nu'cleus,  pi.  Nu'clei.     [Lat.  a  "  kernel."]     A  minute  vesicle  embedded 

in  the  cell  protoplasm  (cytoplasm). 
Nutri'tion.     [From  the  Lat.  nu'trio,  to  "  nourish."]     The  processes  by 

which  the  nourishment  of  the  body  is  accompUshed. 

Occip'ital.     [From  the  Lat.  occiput,  occipitis,  the  "  back  of  the  head."] 

Pertaining  to  the  occiput,  the  back  part  of  the  head. 
Odon'toid.     [From  the  Gr.  odous,  odontos,  a  "  tooth,"  and  eidos,  "  form," 

"  resemblance."]     Tooth-like. 
(Ede'ma.     [From  the  Gr.  aided,  to  "  swell."]     A  swelling  from  effusion  of 

serous  fluid  into  the  areolar  tissue. 
(Esoph'agus.     [Gr.    oisophagos,  from  oiso  (fut.  of  oio)  to    "  carry,"  and 

phagein,  "  to  eat."]     The  gullet. 
Olec'ranon.      [From  the    Gr.   6le7ie,   the   "  elbow,"    and   kranion,   the 

"  head."     The  head  of  the  elbow. 
Olfac'tory.     [From  the  Lat.  olfacio,  olfactum,  to  "  smell."]     Belonging  to 

the  sense  of  smell. 
Omen'tum.     [Lat.  "  coverlet."]    A  dupUcature  of  the  peritoneum,  which 

hangs  in  front  of  the  intestines. 
Ophthal'mic.   [From  the  Gr.  ophthalmos,  the  "  eye."]    Belonging  to  the  eye. 
^  Op'sonins.     [From  the  Gr.  opsono,  "  prepare  food  for."]     A  name  given  to 

chemical  substances  found  in  blood  plasma  which   make  microbes 

more  susceptible  to  phagocytes. 
Op'tic.     [From  the  Gr.  opsis,  "  sight."]     That  which  relates  to  sight. 
Orbicula'ris.     [From  dim.  of  Lat.  orbis,  an  "  orb,"  or  "  circle."]     Name 

of  the  circular  muscles. 
Or'bital.     [From  the  Lat.  orbita,  a  "  track,"  "  rut  of  a  wheel."]     Pertain- 
ing to  the  orbit,  the  bony  ca\'ity  in  which  the  eyeball  is  suspended. 


492  GLOSSARY 

Or'gan.     [From  the  Gr.  organon,  an   "  instmment,  implement,  tool.") 

Any  part  of  the  body  with  a  special  function. 
O'rifice.     [From  the  Lat.  os,  oris,  a  "mouth,"  and  facere,   "to  make."] 

An  opening. 
Os,  pi.  Ora.     [Lat.]    A  mouth. 
Os,  J)!.  Ossa.     [Lat.]     A  bone. 
Os  Cox'ae.     The  hip  bone,  or  os  innominatum. 
Oscilla'tion.     [From  the  Lat.  oscillare,  "to  swing."]     Swinging  backward 

and  forward;  vibration. 
Os'sa  Innomina'ta,  pi.  of  Os  Innomina'tum.     [Lat.]     "  Unnamed  bones." 

The  irregular  bones  of  the  pelvis,  unnamed  on  account  of  their  non- 
resemblance  to  any  known  object. 
Os'seous.     [From  the  Lat.  os,  a  "  bone."]     Consisting  of  or  resembling 

bone. 
Os'sicle.     [From  the  Lat.  ossicvlum,  dim.  of  os,  a  "  bone."]    A  small 

bone. 
Os'teoblasts.     [From  the  Gr.  osteon,  a  "  bone,"  and  blastos,  a  "  germ," 

or  "  sprout."]    The  germinal  cells  deposited  in  the  development  of 

bone. 
O'toliths.     [From  the  Gr.  om.s,  otos,  the  "  ear,"  and  lithos,  a  "  stone."] 

Particles  of  calcium  carbonate  and  phosphate  found  in  the  internal 

ear. 
O'vum.  pi.  O'va.     [Lat.  an  "  egg."]     The  human  germ-cell. 

Pal'ate.  [From  the  Lat.  pala'tum,  the  "  palate."]  The  roof  of  the 
mouth,  consisting  of  the  hard  and  soft  palate. 

Pal'pebra,  pi.  Pal'pebrae.     [Lat.]     The  eyehd. 

Pan'creas.  [From  the  Gr.  pan,  "  all,"  and  kreas,  "  flesh."]  A  compound 
secreting  gland ;  one  of  the  accessory  organs  of  nutrition.  The 
sweetbread   of   animals. 

Papil'lae.  [Lat.  pi.  of  papilla,  a  "  nipple,"  a  "  pimple."]  Minute  emi- 
nences on  various  surfaces  of  the  body. 

Pari'etal.     [From  the  Lat.  paries,  parietis,  a  "  wall."]     Pertaining  to  a  wall. 

Parot'id.  [From  the  Gr.  para,  "  near,"  and  om,  otos,  the  "  ear."]  The 
large  salivary  gland  near  the  ear. 

Parturi'tion.  [From  the  Lat.  parturio,  parturitum,  to  "  bring  forth."] 
The  act  of  bringing  forth,  of  giving  birth  to  young. 

Patel'la.  [Lat  "  a  httle  dish."]  A  small,  6ou7-shaped  bone ;  the  knee- 
pan. 


GLOSSARY  493 

Pec'toral.  [From  the  Lat.  pectus,  pectoris,  the  "  breast."]  Pertaining  to 
the  breast,  or  chest. 

Ped'icle.     [From  the  dim.  of  Lat.  pes,  pedis,  a  "  foot."]    A  stalk. 

Pedun'cle.  [From  the  Lat.  pedunculus,  dim.  of  pes,  a  "  stalk,"  a  "  foot."] 
A  narrow  part  acting  as  a  support. 

Pel'vic.  [From  the  Lat.  pelvis,  a  "  basin."]  Pertaining  to  the  pelvis, 
the  basiii,  or  bony  cavity,  forming  the  lower  part  of  the  ab- 
domen. 

Pep'sin.  [From  the  Gr.  pepto,  to  "  digest."]  A  ferment  found  in  gastric 
juice,  having  power  to  convert  proteins  into  peptones. 

Pep'tone.  [From  the  Gr.  pepto,  to  "  digest."]  A  term  applied  to  protein 
material  digested  by  the  action  of  the  digestive  juices. 

Pericar'dium.  [From  the  Gr.  peri,  "  about,"  "  around,"  and  kardia,  the 
"heart."]     The  serous  membrane  covering  the  heart. 

Perichon'drium.  [From  the  Gr.  peri,  "  about,"  "  around,"  and  chondros, 
a  "  cartilage."]     The  serous  membrane  covering  the  cartilages. 

Per'ilymph.  [From  the  Gr.  peri,  "  about,"  "  around,"  and  the  Lat. 
lympha,  "  water."]  The  fluid  in  the  osseous,  and  surrounding  the 
membranous  labyrinth  of  the  ear. 

Perimys'ium.  [From  the  Gr.  peri,  "  around,"  and  mus,  "  muscle."]  The 
connective  tissue  septa  connecting  and  enveloping  the  separate  fas- 
ciculi of  a  muscle. 

Perine'um.  [From  the  Gr.  perinaion.]  The  region  of  the  body  between 
the  thighs,  extending  from  the  anus  to  the  fourchette  in  the  female, 
or  to  the  scrotum  in  the  male. 

Perios'teum.  [From  the  Gr.  peri,  "  about,"  "  around,"  and  osteon,  a 
"  bone."]     The  membrane  covering  the  bones. 

Periph'eral.  [From  the  Gr.  peri,  "  about,"  "  around,"  and  phero,  to 
"  bear."]  Pertaining  to  the  periphery,  or  circumjerence;  that  which 
is  away  from  the  centre  and  towards  the  circumference. 

Peristal'sis.  [From  the  Gr.  peristello,  to  "  compress."]  Peristaltic  ac- 
tion. A  term  appUed  to  the  worm-like  movement  of  the  intestines 
by  which  its  contents  are  propelled  downward. 

Peritone'um.  [From  the  Gr.  periteino,  to  "  stretch  around,"  to  "  stretch 
all  over."]  The  serous  membrane  lining  the  walls  and  covering  the 
contents  of  the  abdomen. 

Permeable.  [From  the  Lat.  per,  "  through  "  and  meare,  "  to  pass."] 
Capable  of  being  passed  through;  substances  which  allow  the  pas- 
sage of  fluids. 


494  GLOSSARY 

Perone'al.      [From  the  Gr.  perone,  the  "  fibula."]      Pertaining  to  the 

fibula;  a  term  applied  to  muscles,  or  vessels,  in  relation  to  the  fibula. 
Pe'trous.  [From  the  Gr.  petra,  a  "  rock."]  Having  the  hardness  of  rock. 
Phag'ocytes.     [From  the  Gr.  phagein,  "  eat,"  and  kutos,  a  "  cell."    A 

Ij'^mph-corpuscle,  or  white  blood-corpuscle,  regarded  as  an  organism 

capable  of  devouring  what  it  meets,  especially  pathogenic  microbes. 
Phalan'ges.     [Lat.  pi.  of  phalanx,  a  "  closely  serried  array  of  soldiers."] 

A  name  given  to  the  small  bones  forming  the  fingers  and  toes,  be- 
cause placed  alongside  one  another  hke  a  phalanx. 
Phar'ynx.     [From  the  Gr.  pharugx,  the  "  throat."]     The  cavity  forming 

the  upper  part  of  the  gullet. 
Phonation.     [From  the  Gr.  phone,  the   "  voice."]     Utterance   of  vocal 

sounds. 
Phren'ic.     [From  the  Gr.  phren,  the  "  diaphragm."]     Pertaining    to    the 

diaphragm. 
Pi'a  Ma'ter.     [From  the  Lat.  pia  (fem.),  "  tender,"  "  delicate,"  and  mater, 

"  mother."]    The  most  internal  of  the  three  membranes  of    the 

brain. 
Pig'ment.     [From   the   Lat.   pigmentum,   "  paint,"   "  color."]    Coloring 

matter. 
Pin'na.     [Lat.  a  "  feather,"  or  "  wing."]    External  cartilaginous  flap  of 

the  ear.     Same  as  auricle. 
Pi'siform.     [From  the  Lat.  pismn,  a  "  pea,"  and  forma,  "  form."]    Having 

the  form  of  a  pea.     One  of  the  carpal  bones. 
Pitu'itary.     [From  the  Lat.  pituita  "  phlegm."]    Secreting  or  containing 
■  mucus,  or  supposed  to  do  so.     (It  was  formerly  supposed  that  the 

secretions  of  the  nose  proceeded  from  the  brain.) 
Placen'ta.     [From  the  Gr.  plakous,  a  "cake."]     A  flat,  circular,  vascular 

substance  which  forms  the  organ  of  nutrition  and  excretion  for  the 

fa?tus  in  utero. 
Plan'tar.     [From  the  Lat.  planta,  "  the  sole  of  the  foot."]     Pertaining 

to  the  sole  of  the  fooc. 
Platys'ma.     [From    the  Gr.   plains,    "  broad."]     A  thin,   broad  muscle 

situated  immediately  beneath  the  skin  at  the  side  of  the  neck,  and 

extending  from  the  chest  and  shoulder  to  the  face. 
Plex'us.     [From  the  Lat.  plecto,  plexum,  to  "  knit,"  or  "  weave."]    A  net- 
work of  nerves  or  veins. 
Pneumogas'tric.     [From  the  Gr.  pneumon,  a  "  lung,"  and  gaster,  the 

"  stomach."]     Pertaining  to  the  lungs  and  stomach. 


GLOSSARY  495 

Polyhe'dral.     [From  the   Gr.   -polys,    "  many,"   and   hedra,   a   "  side."] 

Many-sided. 
Polysaccharid.      From  the   Gr.   polys,    "many,"   and   Lat.   saccharum, 
"sugar."]     A  complex  sugar,  which  when  decomposed  gives  many 
molecules  of  a  simple  sugar. 
Poplite'al.     [From  the  Lat.  poples,  poplitis,  the  "  ham,"  the  "  back  part 
of  the  knee."]     The  space  behind  the  knee-joint  is  called  the  popliteal 
space. 
Premo'lar.     [From  the  Lat.  proe,  "  before,"  and  molaris,  "  molar."]     An- 
terior in  position  to  a  molar ;  as  premolar  tooth. 
Prismat'ic.     Resembhng  a  prism,  which,  in  optics,  is  a  sohd,  triangular- 
shaped  glass  body. 
Prona'tion.     [From  the  Lat.  pronus,  "  incUned  forwards."]    The  turning 

of  the  hand  with  the  palm  downward. 
Prona'tor.     The  group  of  muscles  which  turn  the  hand  palm  down- 
ward. 
Pro'toplasm.     [From  the  Gr.  protos,  "  first,"  and  plasso,  to  "  form."] 

X  first -formed,  organized  substance;  primitive  organic  cell  matter. 
Pso'as  Mag'nus.     [From  the  Gr.  psoa,  "  loin,"  and  Lat.  magnus,  "  great."] 

A  muscle  of  the  loins  and  pelvis.     The  tenderloin. 
Psy'chical.     [From  the  Gr.  psyche,  the  "  soul."]     Pertaining  to  the  mind. 
Pter'ygoid.     [From  the  Gr.  pterux,  a  "  wing,"  and  eidos,  "  form,"  "  re- 
semblance."]    Wing-Uke. 
Pty'alin.     [From  the  Gr.  ptyalon,   "  saliva."]     A  ferment  principle  in 

saliva,  having  power  to  convert  starch  into  sugar. 
Pu'berty.     [From  the  Lat.   pvher,    "  adult."]     The  age  at  which  re- 
production   becomes    possible;    sexual    maturity    in    the    human 
race. 
Pu'bes,  gen.  Pu'bis.     [Lat.]     The  hairy  region  above  the  genitals,  also 
used  for  os  pubis,  the  portion  of  the  os  innominatum  forming  the 
front  of  the  pelvis. 
Pul'monary.     [From  the  Lat.  pulmo,  pi.  pulmones,  the  "  lungs."]     Re- 
lating to  the  lungs. 
Pulse.     [From  the-  Lat.  pello,  pulsum,  to  "  beat."]    The  striking  of  an 
artery  against  the  finger,  occasioned  by  the  contraction  of  the  heart ; 
commonly  felt  at  the  wrist. 
Pylo'rus.     [From  the  Gr.  pvlouros,  a  "  gate  keeper."]    The  lower  orifice 
of  the  stomach,  furnished  Avith  a  circular  valve  which  closes  during 
stomach  digestion. 


496  GLOSSARY 

Pyrex'ia.  [From  the  Gr.  pyresso,  (fut.)  pyrexo,  to  "  have  a  fever."]  Ele- 
vation of  temperature ;  fever. 

Quad'rate.     [From  the  Lat.  quadratus, ''  make  four-cornered,  or  square."] 

Siiuare.     (A  small  lobe  of  the  liver.) 
Quad'riceps.     [From  the  Lat.  quatuor,  "  four,"  and  caput,  the  "  head."] 

A  term  applied  to  the  extensor  muscle  of  the  leg,  having  four  heads, 

or  parts. 

Rac'emose.  [From  the  Lat.  racemus,  a  "bunch  of  grapes."]  Temi  appUed 
to  compound,  saccular  glands,  from  their  supposed  resemblance  to 
a  bunch  of  grapes. 

Radia'tion.  [From  the  Lat.  radiare,  to  "  furnish  with  spokes  or  wheels."] 
The  (hffusion  of  rays  of  hght. 

Ra'dius.  [Lat.  a  "  rod,"  the  "  spoke  of  a  wheel."]  The  outer  bone  of  the 
forearm,  so  called  from  its  shape. 

Rile.  [From  the  Fr.  raler,  to  "  rattle  in  the  throat."]  A  rattling,  bub- 
bhng  sound  attending  the  circulation  of  air  in  the  lungs.  Different 
from  the  murmur  produced  in  health. 

Rec'tus.  pi.  Rec'ti.  [Lat.]     Straight. 

Reflec'tion.  [From  the  Lat.  re  +  flectere,  to  "bend  or  turn."]  The 
return  of  rays,  beams,  sound,  or  the  like  from  a  surface.  Reflection 
of  light  is  of  two  kinds,  regular  and  diffused.  When  a  beam  of  light 
enters  a  darkened  room  through  a  small  opening  and  strikes  a  mirror, 
a  reflected  beam  will  be  seen  travelling  along  some  definite  path. 
This  is  called  regular  reflection.  Should  the  light,  however,  fall  on 
a  piece  of  white  paper,  it  would  be  reflected  and  scattered  in  all  direc- 
tions. Tliis  is  called  diffused  reflection  and  is  caused  by  the  inequali- 
ties of  the  reflecting  surface.  All  rough  surfaces,  as  well  as  dust  and 
moisture  in  the  atmosphere,  serve  to  diffuse  light.  If  this  were  not 
the  case,  it  would  be  dark  everj'where  except  in  the  direct  path  of 
light  from  some  luminous  body. 

Refrac'tion.  [From  the  Lat.  re  -\- frangere,  to  "break."]  The  bending 
or  deviation  in  tlic  course  of  rays  of  hght  in  passing  obliquely  from 
one  transparent  medium  into  another  of  different  densitj'.  Light 
waves  travel  with  different  velocities  in  mediums  of  different  dei>- 
sities,  the  more  dense  the  medium,  the  less  the  velocity.  For 
instance,  light  will  travel  less  rapidly  in  water  than  in  air.  For 
this  reason  where  a  ray  of  light  in  air  strikes  a  body  of  wat«r 
obliquely,  it  will  be  bent  out  of  a  straight  hne,  as  shown  in  the 


GLOSSARY 


497 


following  diagram;  the  light  ray  AC,  instead  of  following  the 
straight  line  AB,  is  bent  on  striking  the  surface  of  the  dense 
medium,  thereby  being 
bent  from  its  direct  path 
toward  C. 

Re'nal.  [From  the  Lat.  ren, 
rents ,  the  "  kidney . "  ]  Per- 
taining to  the  kidneys. 

Ren'nin.  [Rennet.]  The  milk- 
curdUng  enzyme  which 
constitutes  the  active  prin- 
ciple of  rennet. 

Resil'iency.  [From  the  Lat. 
re,  "  back,"  and  silere,  to 
"  leap."]  The  act  of  resil- 
ing, leaping,  or  springing 
back ;  the  act  of  rebound- 
ing. 

Respira'tion.     [From  the  Lat. 

res'piro,    to    "  breathe   frequently, 
comprising  two  acts, 
or  breathing  out. 

Res'tiform.  [From  the  Lat.  Testis,  a  "  cord,  rope,"  and/orwa,  "  form."] 
In  anatomy  denoting  a  part  of  the  medulla  oblongata,  called  the 
restifonn  bodj'. 

Retic'ular.  [From  the  Lat.  reticulum,  a  "  small  net."]  Resembling  a 
small  net. 

Ret'iform.  [From  the  Lat.  rete,  a  "  net,"  and  forma,  "  form."]  Having 
the  form,  or  structure,  of  a  net. 

Ret'ina.  [From  the  Lat,  rete,  a  "  net."]  The  most  internal  membrane 
of  the  eye ;  the  expansion  of  the  optic  nerve. 

Ru'gae.  [Lat.  pi.  of  ruga,  a  "  wrinkle."]  A  term  applied  to  the  folds,  or 
wrinkles,  in  the  mucous  membrane,  especially  of  the  stomach  and 
vagina. 


The   function   of   breathing, 
inspiration,  or  breathing  in,  and  expiration, 


Sa'crum.     [Lat.  neut.  of  sacer,  "  sacred."]     The  large  triangular  bone 
above  the  coccyx,  so  named  because  it  was  supposed  to  protect  the 
orgarxs  contained  in  the  pehas,  which  were  offered  in  sacrifice  and 
considered  sacred. 
2k 


498  GLOSSARY 

Sag'ittal.     [From  the  Lat.  sagitta,  an  "  arrow."]    Arrow-like. 

Saliva'tion.  [From  the  Lat.  scdivare,  to  "  salivate."]  An  excessive 
secretion  of  saliva. 

Sapi<?.     [From  the  Lat.  sapere,  to  "  taste."]     Possessing  savor  or  flavor. 

Saphe'nous.  [Froni  the  Gr.  saphes,  "  manifest."]  A  name  given  to  the 
two  large  superficial  veins  of  the  lower  limbs. 

Saponifica'tion.  [From  the  Lat.  sapo,  saponis,  "  soap,"  and  facio,  to 
"  make."]     Conversion  into  soap. 

Sarcolem'ma.  [From  the  Gr.  sarx,  sarkos,  "  flesh,"  and  lemma,  a  "  cover- 
ing."]    The  covering  of  the  individual  muscle-fibrils. 

Sarto'rius.  [From  the  Lat.  sartor,  a  "tailor."]  The  name  of  the  muscle 
used  in  crossing  the  legs,  as  a  tailor  does  when  he  sits  and  sews. 

Scaph'oid.  [From  the  Gr.  skaphe,  a  "  boat,"  and  eidos,  "  form."]  Boat- 
shaped.  The  bone  on  the  radial  side  of  the  proximal  row  of  the 
carpus.     Also  called  navicular. 

Scap'ula.     [Lat.]     The  shoulder-blade. 

Scle'ra.  [Lat.  scleroticus,  from  Gr.  skleroo,  to  "  harden."]  Hard, 
tough. 

Se'bum,  or  Se'vum.  [Lat.  sevum,  "  suet."]  A  fatty  secretion  resembUng 
suet,  which  lubricates  the  surface  of  the  skin. 

Secre'tion.  [From  the  Lat.  secer'no,  secre'tum,  to  "  separate."]  The 
process  of  separating  from  the  blood  some  essential,  important  fluid ; 
which  fluid  is  also  called  a  secretion. 

Semilu'nar.  [From  the  Lat.  semis,  "  half,"  and  luna,  the  "  moon."] 
Having  the  shape  of  a  half-moan. 

Ses'amoid.  [From  the  Gr.  sesamon,  a  "  seed  of  the  sesamum,"  and 
eidos,  "  form,"  "  resemblance."]  Resembling  a  grain  of  sesamum. 
A  term  applied  to  the  small  bones  situate  in  the  substance  of  ten- 
dons, near  certain  joints. 

Sig'moid.  [From  the  Gr.  letter  2,  sigma,  and  eidos,  "  form,"  "  resem- 
blance."]    Curved  like  the  letter  S. 

Sole'us.  j^From  the  Lat.  solea,  a  "  sandal."]  A  name  given  to  a  muscle 
shaped  like  the  sole  of  a  shoe. 

Spermatozo'on.  [From  the  Gr.  spermu,  "  sperm  "  (from  speirein,  "  to 
sow  "),  and  zoon,  an  "  animal."]    The  male  generative  cell. 

Sphe'noid.  [From  the  Gr.  sphen,  a  "  wedge,"  and  eidos,  "  form,"  "  re- 
semblance."]    Like  a  wedge. 

Sphinc'ter.  [From  the  Gr.  sphiggo,  to  "  bind  tight,"  to  "  close."]  A  cir- 
cular muscle  which  contracts  the  aperture  to  which  it  is  attached. 


GLOSSARY  499 

Splanch'nic.     [From  the  Gr.  splagchnon,  an  "  entrail."]    Of  or  pertain- 
ing to  the  viscera. 
Squa'mous.     [From  the  Lat.  squama,  a  "  scale."]     Scale-like. 
Sta'sis.     [From   the   Gr.   stao,   to   "  stop."]     Stagnation  of  the   blood 

current. 
Steap'sin.     An  enzyme  of  the  pancreatic  juice  which  has  the  power  of 

decomposing  fats.     Same  as  lipase. 
Stereogno'sis.     [From  the  Gr.  stereos,  "solid,"  and  gnosis,  "knowledge." 

The  faculty  of  recognizing  the  form  or  outline  of  an  object  by  touch- 
ing it. 
Stim'ulus,   pi.    Stim'uli.     [Lat.   a  "goad."]    Anything  that  excites  to 

action. 
Sto'ma,  pi.  Sto'mata.     [From  the  Gr.  stoma,  stomatos,  a  "  mouth."]    A 

mouth;  a  small  opening. 
Stom'ach.     [From  the  Lat.  stomachus,  the  "  throf-t,"  "  gullet,"  also  the 

"  stomach."]     A  more  or  less  sac-like  part  of  the  body  where  food 

is  partially  digested. 
Strat'ified.     [From  the  Lat.  stratum,  a  "  layer,"  and  facio,  to  "  make."] 

Formed  or  composed  of  strata,  or  layers. 
Stri'ated.     [From  the  Lat.  stria,  striatum,  to  "  make  furrows."]     That 

which  has  strioe,  furrows  or  lines. 
Stro'ma.     [From  the  Gr.  stroma,  a  "  bed."]     The  foundation,  or  bed, 

tissue  of  an  organ. 
Styloglos'sus.     [From  the  Gr.  stylos,  a  "  pillar,"  and  glossa,  the  "  tongue."] 

A  muscle  connected  with  a  pointed  style-like  process  of  the  temporal 

bone  and  the  tongue. 
Sty'loid.     [From  the  Gr.  stylos,  a  "pillar,"  and  eidos,  "form."]     A  long 

and  slender  process  from  the  lower  side  of  the  temporal  bone. 
Suc'cus   Enter'icus.     [From   the    Lat.    succus,    "juice,    moisture,"    and 

enteron,  "  intestine."]     Intestinal  juice,  secreted  by  the  intestinal 

glands. 
Sudoriferous.     [From  the  Lat.  sudor,  "  sweat,"  and  fero,  to  "  carry," 

to  "  bear."]    A  term  appUed  to  the  glands  secreting  sweat. 
Sul'cus.     [From    the    Lat.    sulcus,    a    "  furrow,"    "  trench,"    "  ditch," 

"  wrinkle."]    A  fissure  between  two  convolutions  of  the  surface  of 

the  brain. 
Supina'tion.     [From  the  Lat.  supino,  supinatum,  to  "  bend   backward," 

to  "  place  on  the  back."]     The  turning  of  the  hand  with  the  palm 

upward. 


500  GLOSSARY 

Su'pinators.     The  muscles  which  turn  thn  hand  with  palm  upward. 

Supra-re'nal.  [From  the  Lat.  super,  "  over,"  and  ren,  renis,  the  "  kid- 
ney."]    Same  as  adrenal.     A  small  gland  above  each  kidney. 

Su'ture.  [From  the  Lat.  suo,  sutian,  to  "  sew  together."]  That  which 
is  seicn  together,  a  seam ;  the  seam  uniting  bones  of  the  skull. 

Sym'physis.  [From  the  Gr.  syn,  "  together,"  and  phyo,  to  "  produce," 
to  "  grow."]  A  union  of  bones,  usually  of  symmetrical  bones  in  the 
median  line,  as  the  pubic  bones  and  bones  of  the  jaw. 

Syn'apse.  [From  the  Gr.  syn,  "  with,"  and  aptein,  "to  fasten."]  Inter- 
lacing of  terminal  arborizations  of  nerves. 

Synarthro'sis.  [From  the  Gr.  syn,  "  together,"  and  arthron,  a  "  joint."] 
A  form  of  articulation  in  which  the  bones  are  immovably  joined 
together. 

Synchrondro'sis.  [From  the  Gr.  syn,  "  together,"  and  chrondros,  "  carti- 
lage."]    Union  by  an  intervening  growth  of  cartilage. 

Syndesmo'sis.  [From  the  Gr.  syn,  "  together,"  and  desmos,  a  "  liga- 
ment."]    Union  by  ligaments. 

Syno'via.  [Supposed  to  be  from  the  Gr.  syn,  "  together,"  impljing  union 
or  close  resemblance,  and  don,  an  "  egg."]  A  fluid  resembUng  the 
white  of  an  egg. 

Sys'tole.  [From  the  Gr.  systello,  to  "  draw  together,"  to  "  contract."] 
The  contraction  of  the  heart. 

Tac'tile.     [From  the  Lat.  tac'tu^,  "  touch."]     Relating  to  the  sense  of 

toucli. 
Tar'sus.     [From  the  Gr.  tarsos,  the  "  instep."]     The  instep;    also  the 

cartilage  of  the  eyelid. 
Tem'poral.     [From  the  Lat.  tem'pus,  "  time,"  and  tern'pora,  the  "  tem- 
ples."]    Pertaining  to  the  temples;  the  name  of  an  artery  and  of 

a  bone. 
Ten'do  Achil'lis.     [Lat.]     "  Tendon  of  Achilles."     The  tendon  attached 

to  the  heel,  so  named  because  Achilles  is  supposed  to  have  been  held 

by  the  heel  when  his  mother  dipped  him  in  the  river  Styx  to  render 

him  invulnerable. 
Ten'don.     [From  the   Lat.   ten'do,  to  "  stretch."]     The  white,  fibrous 

cord,  or  band,  by  which  a  muscle  is  attached  to  a  bone ;  a  sinew. 
Thermogenet'ic.     [From  the  Gr.  therme,  "  heat,"  and  gignere,  "  to  beget."! 

Name  given  to  centre  in  brain,  supposed  to  be  concerned  with  the  pro 

duction  of  heat. 


GLOSSARY  501 

Thermolyt'ic.    [From  the  Gr.  therme,  "  heat,"  and  luein,  "  to  loose."]    Name 

given  to  centre  in  brain  supposed  to  be  concerned  in  the  dissipation 

of  heat. 
Thermotac'tic.     [From  the  Gr.  therme,  "  heat,"  and  taxis,  "  arrangement."] 

Name  given  to  centre  supposed  to  regulate  the  thermogenetic  and 

thermolj^tic  centres. 
Thorac'ic.     [From  the  Gr.  thorax,  a  "  breastplate,"  the  "  breast."]     Per- 
taining to  the  thorax. 
Throm'bus.     [From  the  Gr.  thrombus,  a  "lump,"  a  "  piece."]     Name  given 

to  a  clot  formed  in  a  blood-vessel. 
Thy'mus.     [From  the  Gr.  thymo,  "thyme."]    The  shape  of  the  thymus 

gland  was  thought  to  resemble  the  flowers  of  thyme,  hence  the  name. 
Thy'roid.     [From  the  Gr.  thyreos,  an  "  oblong  shield,"  and  eidos,  "  form," 

"  resemblance."]     Resembling  a  shield.     A  name  given  to  an  opening 

in  the  ossa  innominata ;  to  the  piece  of  cartilage  forming  the  anterior 

prominence  of  the  larynx ;  and  to  the  gland  placed  in  front  of  the 

larynx. 
Tib'ia.     [Lat.  a  "  flute,"  or  "pipe."]     The  shin-bone,  called  tibia,  irora 

its  fancied  resemblance  to  a  reed-pipe. 
Tibialis  Ante'rior.    [Lat.]     The  muscle  situated  at  the  anterior  part  of  the 

tibia. 
Tis'sue.     [From  the  Lat.  texere,  "  weave."]    An  aggregate  of  similar  cells 

and  cell-products  in  a  definite  fabric. 
Tox'ic.     [From  the  Lat.  toxicum,  "poison."]     Poisonous. 
Trabec'ulae.     [Lat.  pi.  of  trabecula,  a  "  little  beam."]    A  term  applied 

to  prolongations  of  fibrous  membranes  which  form  septa,  or  partitions. 
Transversa'Iis.     [Lat.  from  trans,  "  across,"  andverto,  versum,  to  "  turn," 

to  "  direct."]     A  term  applied  to  a  muscle  which  runs  in  a  trans- 
verse direction. 
Trape'zius.     [From  the  Gr.  trapeza,  "  table."]    A  name  given  to  the  two 

upper  superficial  muscles  of  the  back,  because  together  they  resemble 

a  trapezium,  or  diamond-shaped  quadrangle. 
Trapezoid'.     [From  the  Gr.  trapeza,  "  table,"  and  eidos,  "  form."]     One 

of  the  bones  of  the  wrist.     The  second  one  of  the  distal  row  on  the 

radial  or  thumb  side. 
Tri'ceps.     [From  the  Lat.  tres,  "  three,"  and  caput,  the  "  head."]     A  term 

applied  to  a  muscle  having  a  triple  origin,  or  three  Iieads. 
Tricus'pid.     [From  the  Lat.  tres,  "  three,"  and  cuspis,  ciispidis,  a  "  point." J 

Having  three  points. 


502  GLOSSARY 

Trochanter.     [From  the  Gr.  trochao,  to  "  turn,"  to  "  rev'olve."]     Name 

given  to  two  projections  on  the  upper  extremities  of  the  femur, 

wliich  give  attachment  to  the  rotatoi  muscles  of  the  tliigh. 
Trsrp'sin.     The  enzyme  in  pancreatic  juice  which  converts  protein  material 

into  peptones. 
Tuberos'ity.     [From  the  Lat.  tvber,  tuberis,  a  "  sweUing."]    A  protuberance. 
Tu'bular.     [From  the  Lat.  tubulus,  a  "  small  pipe."]     Having  the  form  of 

a  tul)e,  or  pipe. 
Tur'binated.     [Lat.  turbinatus,  from  turbo,  turbinis,  a  "  top."]     Fomied 

like  a  top ;  a  name  given  to  the  bones  in  the  outer  wall  of  the  nasal 

fossa". 
Tym'panum.     [From  the  Gr.  tympanon,  a  "  drum."]     The  drum,  or  hollow 

part,  of  the  middle  ear. 

Ul'na.  [Lat.  the  "  elbow."]  The  inner  bone  of  the  forearm,  the  olecranon 
jirocess  of  which  forms  the  elbow. 

Umbili'cus.  [Lat.  the  "  navel."]  A  round  cicatrix,  or  scar,  in  the  me- 
dian line  of  the  abdomen. 

Un'ciform.  [From  the  Lat.  uncus,  a  "  hook,"  and  forma,  "  form."] 
Hooked,  or  crooked.  One  of  the  bones  of  the  wrist,  so  called  from 
its  hook-like  process. 

U'rea.  [From  the  Lat.  urina,  "  urine."]  Cliief  soUd  constituent  of 
urine. 

Ure'ter.  [From  the  Gr.  oureo,  to  "  pass  urine."]  The  tube  through 
which  the  urine  is  conveyed  from  the  kidney  to  the  bladder. 

Ure'thra.  [From  the  Gr.  oureo,  to  "  pass  urine."]  The  canal  through 
which  the  urine  is  conveyed  from  the  bladder  to  the  meatus  urinarius. 

Urinif'erous.  [From  the  Lat.  urina,  "urine,"  and  fer re,  "bear."]  Con- 
veying urine,  as  urinferous  tubes,  or  ducts. 

U'vula.  [Dim.  of  Lat.  uva,  a  "  grape."]  The  small,  elongated,  fleshy 
body  hanging  from  the  soft  palate. 

Vag'inal.     [From  tlie  Lat.  vagina,  a  "  sheath."]     Sheath-hke. 

Val'vulae  Conniven'tes.     [Lat.]    A  name  given  to  transverse  folds  of  the 

mucous  membrane  in  the  small  intestine.     More  recent   term  is 

"  circular  folds." 
Vas'cular.     [From   the   Lat.  vasculum,  a  "  little  vessel."]     Relating  to 

vessels;  full  of  vessels. 
Va'so-constric'tor.     [From  the  Lat.  vas,  a  "  vessel,"  and  constringo,  to 

"  constrict."]    An  agent  which  brings  about  constriction  of  blood- 


GLOSSARY  503 

vessels  ;  specifically  a  nerve  when  stimulated,  or  a  drug  which  acts 

in  this  way  when  administered. 
Va'so-dila'tor.     [From  the  Lat.  vas,  a  "  vessel,"  and  dilator,  a  "  dilator."] 

An  agent  which  brings  about  dilatation  of  blood-vessels. 
Ve'nae  Ca'vse,  pi.   of   Ve'na   Ca'va.     [Lat.]   "  Hollow  veins."    A  name 

given  to  the  two  great  veins  of  the  body  which  convey  the  blood 

to  the  right  auricle  of  the  heart. 
Ven'tral.     [From  the  Lat.  venter,  ventris,  the  "  belly."]    The  front  surface 

of  the  body. 
Ven'tricle.     [From  the  dim.  of  Lat.  venter,  the  "  belly."]    A  small  cavity. 
Ver'miform.     [From  the  Lat.  vermis,  a  "  worm,"  and  forma,  "  form."] 

Worm-shaped. 
Ver'nix  Caseo'sa.     [Lat.]     "  Cheesy  varnish."    The  fatty  varnish  found 

on  the  new-born  infant,  which  is  secreted  by  the  sebaceous  glands  of 

the  skin. 
Ver'tebrae,  pi.  of  Ver'tebra.     [Lat.  from  verto,  to  "  turn."]     The  bones 

of  the  spine. 
Vibration.     [From  the  Lat.  vihrare,  to  shake.]    The  act  of  moving  rapidly 

to  and  fro. 
Vil'li.     [Lat.  pi.  of  villus,  "  shaggy  hair."]     The  conical  projections  on 

the  valvulae  conniventes,  making  the  mucous  membrane  look  shaggy. 
Vitel'lus.     [Lat.  vitellus,  a  "  yolk."]     The  yolk  of  an  egg. 
Vit'reous.     [From    the    Lat.    vitrum,     "  glass."]    Glass-like.    A    name 

applied  to  the  transparent,  jelly-like  substance  which  fills  the  back 

part  of  the  eyeball  behind  the  crystalline  lens. 
Vo'mer.     [Lat.  a  "  ploughshare."]    The  thin  plate  of  bone  shaped  some- 
what like  a  ploughshare  which  separates  the  nostrils. 

Xi'phoid.  [From  the  Gr.  xiphos,  "  sword,"  and  eidos,  "  form."]  Shaped 
Uke  or  resembling  a  sword,  ensiform. 

Zygomat'ic.  [From  the  Gr.  zygos,  "  yoke,"  "  join."]  Of  or  pertaining 
to  the  malar  bone  or  this  bone  and  its  connections.  Constituting  or 
entering  into  the  formation  of  the  zygoma. 

Zymogen.  [From  the  Gr.  zwme,  "leaven"  and  ^ig'nere,  "  to  beget."]  A 
mother  substance  or  antecedent  of  an  enzyme. 


INDEX 


(And  see  Glossary,  pages  471  to  503) 


Abdomen,  divisions  of,  261. 

muscles  of,  102,  107,  123. 
action  of,  109. 

regions  of,  261,  262. 
Abdominal  cavity,  20. 

ring,  external,  109. 
internal,  109. 

wall,  weak  places  in,  109. 
Abducens  nerve,  396. 
Abduction,  87. 
Absorption,  301,  306. 

paths  of,  301,  306. 
Accessory  thyroids,  314. 
Accommodation,  431,  441. 

conditions  affecting,  431,  441. 
Acetabulum,  75. 
Acetone,  in  urine,  337. 
Acid,  7. 

oxide,  7. 
Acromegaly,  317. 
Acromion  process,  71. 
Adam's  apple,  235. 
Adduction,  87. 

Adductor  muscles  of  thigh,  115. 
Adenoid  tissue,  40. 
Adenoids,  260. 
Adenology,  definition  of,  14. 
Adipose  tissue,  38. 
Adolescence,  period  of,  452. 
Adrenal  bodies,  316,  322. 
Adrenalin,  316. 

Afferent  nerve  fibres,  371,  372,  403. 
Air,  complementary,  245. 

composition  of,  246. 

effect  of  respiration  upon  the,  246. 

expired,  246. 

inspired,  246. 

reserve,  246. 

residual,  246,  253. 

tidal,  245. 
Akinesis,  24. 
Albumins,  148. 

as  food,  287. 

in  urine,  336. 
Albuminuria,  336. 
Alexia,  394. 

Alimentary  canal,  254,  279. 
divisions  of,  255. 

system,  26,  32. 
Alkalies,  7. 
Alveoli  of  lungs,  240. 


Amoeba,  23. 

Amoeboid  movement,  145. 

Amphiarthroses,  84,  88. 

Ampulla  of  .semicircular  canals,  419. 

Amylopsin,  297. 

Anabolism,  23,  308. 

Anastomosis  of  arteries,  184,  185. 

Anatomical  position,  14. 

Anatomy,  definition  of,  14. 

divisions  of,  14. 
Anemia,  144. 

Angiology,  definition  of,  14. 
Annular  ligaments,  118. 
Antibodies,  in  blood,  149,  158. 
Antitoxins,  in  blood,  158. 
Antrum,  of  bone,  52. 

of  Highmore,  63. 
Anus,  271. 
Aorta,  188. 

abdominal,  189,  193,  211. 

arch  of,  188,  211. 

ascending,  197,  211. 

branches  of,  190,  211. 

descending,  188. 

thoracic,  188,  193,  211. 
Aphasia,  394. 
Apnoea,  247. 
Aponeurosis,  37,  94. 
Appendix,  vermiform,  270. 
Aqueduct  of  Sylvius,  392. 
Aqueous  humor,  429,  440. 
Arachnoid,  384. 
Arborizations,  end,  369. 

interepithelial,  369. 
Arch,  palmar,  193. 
Areas  of  brain,  393,  407. 
Areola,  35. 

of  mammary  gland,  454. 
Areolar  tissue,  34. 
Arm  bone,  71. 

Arrector  muscles  of  hairs,  348. 
Arterial  tone,  170. 
Arterioles,  170. 
Artery,  or  arteries,  161, 168,  181. 184,  2ia 

anastomosis  of,  184,  185. 

aorta,  188,  211. 

axillary,  192. 

basilar,  192. 

blood  supply  of,  169. 

brachial,  192. 

branches  of,  185. 


505 


506 


INDEX 


Artery,  or  arteries  —  continued 

bronchial,  193. 

carotid,  common,  190. 
external,  191. 
internal,  191. 

cceliac  axis,  194. 

diWsion  of,  185. 

distribution  of,  219. 

dorsal,  of  foot,  200. 

elasticity  of,  217. 

extensibility  of,  217. 

femoral,  198. 

gastric,  194. 

hemorrhoidal,  superior,  195. 

hepatic,  194,  277. 

hypogastric,  197. 

iliac,  common,  197,  212. 
external,  198. 
internal,  198. 

innominate,  190. 

inosculation  of,  185. 

intcrcostalcs,  193. 

lumbar,  197. 

mediastinal,  posterior,  193. 

mesenteric,  inferior,  195. 
superior,  194. 

nerve  supply  of,  169. 

oesophageal,  193. 

ovarian,  197. 

pericardial,  193. 

peroneal,  200. 

phrenic,  197. 

plantar,  external,  200. 
internal,  200. 

plexus  of,  185. 

popliteal,  200. 

pulmonarj',  185. 

radial,  193. 

renal,  195. 

sacral,  middle,  197. 

severed,  flow  of  blood  from,  219. 

sheath  of,  170. 

size  of,  170. 

spermatic,  197. 

splenic,  194. 

structure  of,  168. 

subclavian,  192. 

suprarenal,  196. 

tibial,  anterior,  200. 
posterior,  200. 

tone  of,  170. 

ulnar,  193. 

uterine,  198. 

vertebral,  192. 
Arterial  tone,  170. 
Arterioles,  170. 
Arthrodia,  88. 

Articulations,  82  ;   and  see  Joints. 
Ascending  tracts  of  spinal  cord,  380. 
Asphyxia,  248. 

Association  areas  of  brain,  395,  407. 
Astigmatism,  432,  441. 
Atlas,  66. 


Atom,  3,  6. 
Attraction  sphere,  22. 
Auditory  apparatus,  414,  434. 

canals,  415,  435. 

nerve,  419,  436. 
Auricle  of  ear,  415,  435. 
Auricles  of  heart,  164. 
Automaticity  of  mu.scle,  93. 
Autonomic  nervous  system,  376. 
Axillary,  artery,  192. 

vein,  204,  212. 
Axis,  66. 

cylinder  process,  366,  367,  402. 
Axon,  366. 
Azygos  veins,  207. 

Bacteria,  action  of,  in  large  intestine,  300. 

in  small  intestine,  299. 
Bacteriolysins,  145. 
Bartholin,  gland  of,  451. 
Base,  7. 
Basic  oxide,  7. 

Basilar  membrane  of  ear,  419,  436. 
Baths,  cold,  356. 

hot,  356. 

regulation  of  heat  by,  356. 
Biceps,  of  arm.  111. 

of  thigh,  115. 
Bicuspid,  teeth,  259. 

valve,  166,  181. 
Bile,  298,  305. 

action  of,  298. 

duct,  common,  277. 

ducts,  277,  284. 

-secreting  function  of  liver,  278. 
Bladder,  331.  340. 
Blastoderm,  27,  33. 
Blind  spot,  428. 
Blood,  141,  155. 

antibodies  in,  149,  158. 

antitoxins  in,  158. 

changes  in,  in  inflammation,  145,  157. 

characteristics  of,  141. 

circulation  of,  214  ;  and  see  Circulation. 

clotting  of,  149 ;   and  see  Coagulation 
of  blood. 

coagulability  of,  150,  159. 

composition  of,  142,  147,  155. 

defibrinated,  151. 

difference  between  Ij-mph  and,  153. 

distribution  of,  219,  229. 

effects  of  respiration  upon,  245,  253. 

extractives  in,  141. 

functions  of,  141,  155. 

gases  in,  141. 

haemoglobin,  143. 

in  urine,  338. 

interchange  between  lymph  and,  154. 

internal  secretions  in,  149,  158. 

opsonins  in,  158. 

plasma,  142,  147,  157. 

-plates,  146,  157. 

proteins  in,  147. 


INDEX 


507 


Blood  —  continued 
quantity,  141. 
rate  of  flow  of,  219. 
regeneration  of,  after  hemorrhage,  152, 

159. 
salts  in,  147. 
serum,  159. 
summary  of,  155. 
Blood-corpuscles,  142,  155. 
red,  142,  155. 

differences  between  white  and,  146, 
157. 

function  of,  143,  155. 

life  cycle  of,  143,  156. 

number  of,  144,  156. 
white,  144,  156. 

differences  between  red  and,  146, 157. 

function  of,  145,  156. 

life  cycle  of,  146,  156. 

number  of,  144,  156. 

varieties  of,  144,  156. 
Blood-pressure,  219,  229. 
arterial,  219,  229. 
capillary,  22a,  230. 
effect  of  respiration  on,  220. 
method  of  determining,  221,  230. 
normal  degree  of,  221,  230. 
venous,  220,  230. 
Blood-vascular  system,  161,  180. 
Blue  baby,  224. 
Bodily  heat,  352. 
distribution  of,  353. 
loss  of,  353,  361. 
production  of,  352,  361. 
regulation  of,  354,  355,  362. 
variations  in,  357. 
Body,  back  view  of,  16. 
cavities  of,  17. 

contents  of,  18,  20. 
chemical  elements  in,  5. 
front  view  of,  15. 
human,  17,  20. 
structural  units  of,  21. 
surfaces  of,  14. 
Bone,  or  bones,  42. 
atlas,  66. 
axis,  66. 

blood  vessels  of,  44. 
calcaneum,  80. 
canaliculi  of,  44. 
cancellated,  43. 
classification  of,  49,  81. 
clavicle,  70. 
coccyx,  68. 
compact,  43. 
composition  of,  42,  48. 
dense,  43. 

depressions  of,  51,  52. 
digits,  of  foot,  80. 

of  hand,  74. 
epistropheus,  66. 
ethmoid,  57. 
femur,  77. 


Bone,  or  bones  —  continued 
fibres  of  Sharpey,  44. 
fibula,  78. 
flat,  51. 
frontal,  54. 
functions  of,  49,  81. 
growth  of,  46. 
Haversian  canals,  44. 

system,  44. 
humerus,  71. 
hyoid,  63. 
ilium,  75. 
incus,  416. 

inferior  turbinated,  60. 
irregular,  51. 
ischium,  75. 
lacrimal,  61. 
lacunse  of,  44. 
lamellae  of,  43. 
long,  49. 
lower  jaw,  63. 
malar,  61. 
malleus,  416. 
mandible,  63. 
marrow,  44. 
maxilla,  62. 
maxillary,  inferior,  63. 

superior,  62. 
medullary  canal  of,  43,  50. 
metatarsus,  80. 
nasal,  60. 
number  of,  49. 
occipital,  53. 
of  arm,  71. 
of  calf,  78. 

of  carpus,  72,  73.  81. 
of  cranium,  53. 
of  ear,  81,  416. 
of  elbow,  .72. 
of  face,  60,  81. 
of  foot,  79,  80. 
of  hand,  74. 
of  head,  52,  81. 
of  heel,  80. 
of  hip,  74. 
of  instep,  80. 
of  leg,  74. 

of  lower  extremities,  74,  81. 
of  metacarpus,  74. 
of  metatarsus,  80. 
of  skull,  52. 
of  sole,  80. 
of  tarsus,  78,  81. 
of  thigh,  77. 
of  thorax,  68. 
of  trunk,  64,  81. 
of  upper  extremities,  69,  81. 
of  wrist,  72,  73. 
palate,  61. 
parietal,  54. 
patella,  77. 
pelvis,  75. 
periosteum  of,  44. 


508 


INDEX 


Bone,  or  bones  —  continued 

phalanges,  of  foot,  80. 
of  hand,  74. 

processed  of,  51,  52. 

pubes,  75. 

radiu-s,  72. 

regeneration  of,  4G. 

ribs,  69. 

saenim,  68. 

scapula,  71. 

sesamoid,  49. 

shin.  78. 

short,  51. 

sphenoid,  58. 

spongy,  4.3. 

stapes,  416. 

sternum,  68. 

structure  of,  4.3,  45. 

summary  of,  46,  48,  81. 

table  of,  81. 

temporal,  55. 

tibia,  78. 

ulna,  72. 

upper  jaw,  62. 

varieties  of,  48. 

vertebrae,  64,  65,  81. 

vomer,  60. 
Brachial,  artery,  192. 
Brain,  383,  406 ;  and  see  Cerebrum. 

association  areas  of,  395. 

divisions  of,  385,  406. 

function,  localization  of,  393. 

membranes  of,  384,  406. 

motor  areas  of,  393. 

sense  areas  of,  394. 

speech  areas  of,  394. 

stnicturc  of,  384. 

summary,  406. 

ventricles  of,  391,  392. 

weight  of,  385. 
Breast  bone,  68  ;   and  see  Sternum. 
Breasts,    453,   465 ;    and  see  Mammary 

,  glands. 
Breathing,  see  Respiration. 

nasal,  advantages  of,  234,  250. 
Broad  ligaments  of  uterus,  447. 
Bronchi,  238,  251. 
Bronchial,  arteries,  193. 

tubes,  238. 
Bronchioles,  238. 
Brunner's  glands,  268. 
Buccal  cavity,  19,  20,  255,  279. 
Buccinator,  100. 
BursjE,  synovial,  129. 

Csecum,  270. 
Calcaneum,  80. 
Calculi,  .3.37. 
Calf  bone,  78. 
Callus,  46. 

Calorie,  12,  311.  321. 

'    large,  13,  311,  .321. 

small,  12,  311,  .321. 


Calyces  of  kidney,  339. 
Canal,  or  canals,  52. 

auditory,  435. 

inguinal,  109. 

semicircular,  419,  430. 
Canaliculi,  of  bone,  44. 
Cancelli,  of  bone,  43. 
Canine  teeth,  259. 
Canthus,  of  eye,  422. 
CapUlaries,  161,  170,  181. 

distribution  of.  170. 

function  of,  171. 

influence  of,  on  circulation,  218. 

structure  of,  170. 
Capsule  of  Tenon.  424. 
Carbohydrates,  288.  303. 

function  of,  310,  320. 

metabolism  of,  309,  310,  320. 
Carbon  dioxide,  246. 
Cardiac  muscle,  91. 
Carotid  arteries,  common,  190. 

external,  191. 

internal,  191. 
Carotid  glands,  317.  322. 
Carpus,  bones  of,  72,  73,  81. 
Cartilage,  40. 

cricoid,  235. 

elastic,  41. 

hyaline,  40. 

summary  of,  47. 

thyroid,  235. 

true,  40. 

varieties  of,  40. 

white  fibro-,  40. 

yellow,  41. 
Ciiseinogen,  287,  295. 
Casts,  in  urine,  337. 
Cauda  ccjuina,  396. 
Cavities,  abdominal,  20. 

buccal,  19. 

cranial,  IS. 

dorsal,  18. 

glenoid,  of  scapula,  71. 

nasal,  19,  234,  250. 

of  body.  17,  20. 
contents  of,  20. 

orbital,  19. 

pelvic,  20. 

thoracic,  19. 

ventral,  18. 
Cell,  or  cells,  21. 

amoeboid  movement  of,  23. 

bipolar,  366. 

differences  in,  24,  32. 

life  activities  of,  22,  32. 

mastoid,  56. 

meanings  of  term,  21,  56. 

metabolism  of,  23. 

multipolar,  366. 

nerve,  364,  402. 

prickle,  30. 

reproduction  of,  24. 

respiration  in,  22. 


INDEX 


509 


Cell,  or  cells  — -  continued 

summary,  32. 

unipolar,  366. 

wandering,  145. 
Cell-division,  24. 
Central  canal  of  cerebro-spinal  system, 

391. 
Central  lobe  of  cerebrum,  391. 
Centres,  in  medulla,  386. 

nerve,  374,  404. 
Centrifugal  fibres,  371. 
Centripetal  fibres,  371. 
Centrosome,  22. 
Cerebellum,  386,  406. 

functions  of,  386,  406. 

peduncles  of,  386. 
Cerebro-spinal  nerves,  363. 
Cerebrum,  388,  406. 

areas  of,  393. 

convolutions  of,  388,  406. 

cortex  of,  388. 

fissures  of,  388,  390,  406,  407. 

functions  of,  393. 

lobes  of,  391,  407. 

localization  of  function  in,  393. 

sulci  of,  388,  406. 
Ceruminous  glands,  350. 
Change,  4. 

chemical,  4. 

physical,  4. 
Chemical  change,  4. 

equation,  6. 

formula,  6. 
Chemistry,  3. 

Chest,  muscles  of,  102,  103,  123. 
Cheyne-Stokes  respiration,  248. 
Chordae  tendinese,  166. 
Choroid,  425,  439. 
Chyle,  153,  160. 
Chyme,  293. 
Ciliary  body,  426,  439. 

processes,  426,  439. 
Ciliated  epithelium,  28. 
Circle  of  Willis,  191. 
Circulation,  of  blood,  214,  228. 

changes  in,  in  inflammation,  145,  157. 

diagram  of,  215. 

factors  governing,  215,  228. 

fcetal,  224,  231. 

influence  of  capillaries  on,  218. 

influence  of  elasticity  and  extensibility 
of  arteries  on,  217. 

pulmonary,  214,  228. 

rate  of,  219. 

summary  of,  228. 

systemic,  215,  228. 
Circumduction,  87. 
Circumvallate  papilliB,  411. 
Clavicle,  70. 
Climacteric,  452. 
Clitoris,  450. 

Clothing,  regulation  of  bodily  heat  by, 
356. 


Coagulation  of  blood,  149,  159. 
conditions,  affecting,  150,  159. 
hastening,  150,  159. 
hindering,  151,  159. 
intravascular,  152,  159. 
value  of,  150,  159. 
Coccygeal  gland,  317,  322. 
Coccyx,  68. 
Cochlea,  419,  436. 
Cochlear  nerve,  419,  436. 
Coeliac  axis,  194. 
Collar  bone,  70. 
Collateral  ganglia,  376,  405. 
Collaterals,  367,  368,  402. 
Colon,  270. 

ascending,  270. 

descending,  270. 

transverse,  270. 
Colostrum,  456,  466. 
Columnar  epithelium,  28. 
Complementary  air,  245. 
Compounds,   3. 

inorganic,   5. 

organic,    5. 
Conduction,  nerve,  383. 
Condylarthrosis,  88. 
Condyles,  of  bone,  52. 

of  femur,  77. 
Conjunctiva,  423. 
Connective  tissues,  34. 

adenoid,  40. 

adipose,  38. 

areolar,  34. 

bone,  42. 

cartilage,  40. 

elastic,  37. 

fibrous,  35. 

lymphoid,  40. 

reticular,  39. 

retiforra,  39. 

summary  of,  46. 

varieties  of,  46. 
Constipation,  299,  300. 
Contractility,  muscular,  91. 
Cord,  umbUical,  224. 
Corium,  344,  345. 
Cornea,  425,  439. 
Coronary  veins,  201. 
Corpora  Arantii,  167. 
Corpuscles,    blood,    142,    155 ;     and   see 
Blood  corpuscles. 

Malpighian,  of  kidneys,  327,  339. 
of  spleen,  318. 

of  Meissner,  410. 

of  Pacini,  370,  459. 

red,  142,  155. 

renal,  327,  339. 

tactile,  370. 

white,  144,  156. 
Corpus  callosum,  388. 

luteum,  444. 
Corti,  organ  of,  419. 
Coughing,  249. 


510 


INDEX 


Cowper's  glands,  460,  468. 
Cranial  cavity,  18,  20. 

nerves,  304,  395. 
Cranium,  bones  of,  53. 
,Creatinin,  in  urine,  336. 
Crest,  of  bone,  52. 

of  ilium,  75. 
Cretinism,  314. 
Cricoid  cartilage,  235. 
Crjing,  249. 

Crypts  of  Licberkiihn,  267. 
Crystalline  lens,  430,  440. 
Cutaneous  membrane,  134. 
Cutis  vera,  344,  345. 
Cystic  duct,  277. 
Cytoplasm,  22. 

Decidua  serotina,  462. 

vera,  462. 
Decussation  of  nerve  fibres,  385. 
Defecation,  300. 
Degeneration  of  nerves,  382. 
Deglutition,  292. 
Dehydration,  9. 
Deltoid,  110. 
Dendrites,  366,  402. 
Dentine,  258. 
Derma,  345,  359. 
Dermatologj',  definition  of,  14. 
Descending  tracts  of  spinal  cord,  380. 
Diabetes  mellitus,  273. 
Dialysis,  12,  154. 
Diapedesis,  145. 
Diaphragm,  19,  20,  105. 
Diarthroses,  85,  88. 
Diastase,  297. 
Diastole,  216. 
Diet,  Moleschott's,  312. 

Ranke's,  312. 

regulation  of  bodily  heat  by,  355. 
Diffusion,  9. 
Digestion,  254,  286,  302. 

accessory  organs  of,  271. 

chemical,  290. 

in  mouth,  291. 

time  required  for,  293. 

in  stomach,  293,  305. 

intestinal,  295,  305. 

mechanical,  289. 

necessity  for,  289. 

processes  of,  289,  303. 

summary  of,  279. 

temperature  necessary  for,  292. 
Digestive  fluids,  enzymes  in,  304. 

processes,  289,  303. 
chemical,  290. 
mechanical,  289. 

sj'stem,  254,  279. 
Digits,  of  foot,  79,  80. 

of  hand,  74. 
Diploe,  58. 

Disaccharids,  as  food,  288. 
Discus  proligerus,  443. 


Disks,  intervertebral,  66. 

Dislocation,  87. 

Distal,  17. 

Dorsal  artery  of  foot,  200. 

cavity,  18,  20. 

surface,  14. 
Douglas,  pouch  of,  448. 
Duct,  bile,  277. 

common  bile,  277. 

cystic,  277. 

ejaculatory,  458,  467. 

hepatic,  277. 

nasal,  423. 

thoracic,  174,  182. 
Ductless  glands,  313,  321. 
Ductus  arteriosus,  224. 

communis  cholcdochus,  277. 

venosus,  224. 
Duodenal  glands,  268. 
Duodenum,  265. 
Dura  mater,  384. 
Dyspncca,  247. 

Ear,  bones  of,  416. 

external,  414,  435. 

internal,  417,  436. 

middle,  416,  435. 
Ectoderm,  27,  33. 

Efferent  nerve  fibres,  371,  372,  403. 
Ejaculatory  ducts,  458,  467. 
Elastic  tissues,  36,  37. 
Elasticity  of  muscle,  92. 
Elbow  bone,  72. 
Elements,  3,  21. 

in  human  body,  5. 
Elimination,  324,  338. 

organs  of,  324,  338. 
Embolus,  152,  159. 
Embryo,  462. 
Emulsion,  12. 
Enarthrosis,  88. 
End  arborizations,  369. 
Endocardium,  164. 
Endolymph,  418. 
Endosteum,  43,  48. 
Endothelium,  127. 
Energy,  9. 

Ensiform  process,  69. 
Entoderm,  27,  33. 
Enzj-mes,  291,  303. 

in  blood,  149,  158. 

in  digestive  fluids,  304. 
Epidermis,  28,  344,  359. 
Epigastric  region  of  abdomen,  262. 
Epiglottis,  235,  236. 
Epimysium,  94. 
Epiphysis,  317,  322. 
Epistropheus,  66. 

Epithelial  tissue,  27 ;  and  see  Epithelium. 
Epithelium,  27. 

ciliated,  28. 

columnar,  28. 

functions  of,  31,  33. 


INDEX 


511 


Epithelium  —  continued 

pavement,  28. 

simple,  28. 

stratified,  30. 

summary  of,  33. 

transitional,  29. 

varieties  of,  28. 
Equation,  chemical,  6. 
Equilibrium,  nitrogen,  311,  320. 

sense  of,  420,  437. 
ErectUe  tissues,  459. 
Ethmoid  bone,  57. 
Eustachian  tubes,  416,  435. 

valve,  168. 
Excitatory  nerve  fibres,  372,  403. 
Excreta,  324,  338. 

discharge  of,  325,  338. 
Excretion,  137. 

table  of,  140. 
Excretory  organs,  324,  338. 

system,  26,  32. 
Exercise,  regulation  of  bodily  heat  by, 

355. 
Exophthalmic  goitre,  315. 
Expiration,  242,  252. 
Expression,  muscles  of,  100. 
Extensibility  of  muscle,  92. 
Extension,  87. 
Extensor  muscles,  of  forearm,  112. 

of  leg,  126. 
External,  17. 

External  oblique  muscle  of  abdomen,  107. 
Extractives,  as  food,  287. 

in  blood,  147,  148,  158. 
Extremities,  20. 
Eye,  accessory  organs  of,  421. 

canthus  of,  422. 

muscles  of,  97,  423,  438. 

nerves  of,  423,  438. 

pupil  of,  426,  440. 

white  of,  425. 

window  of,  425. 
EyebaU,  425,  439. 

dimensions,  439. 

muscles  of,  97,  423,  438. 

refracting  media,  425,  439. 

tunics,  425,  439. 
Eyebrows,  421,  437. 
Eyelashes,  421. 
Eyelids,  421,  437. 

Face,  52. 

bones  of,  60. 

muscles  of,  95,  97. 
Facial  nerve,  396. 
Fallopian  tubes,  444,  464. 
Falx  cerebri,  388. 
Fascia,  or  fascije,  37,  118. 

deep,  37. 

lumbar,  107. 

palmar,  37. 

plantar,  37. 

superficial,  37. 


Fatigue,  94,  410,  433. 
Fats,   action  of  pancreatic  juice  upon, 
297. 

as  food,  289,  303. 

decomposition  of,  289. 

digestion  of,  290. 

function  of,  309. 

in  blood,  148,  158. 

metabolism  of,  308,  320. 
Fauces,  257. 
Feces,  300. 
Female  generative  organs,  442. 

physiology  of,  451. 
Femoral,  artery,  198. 

vein,  206,  213. 
Femur,  77. 
Fenestra,  ovalis,  416,  435. 

rotunda,  416,  436. 
Fever,  358,  362. 
Fibrin,  150. 
Fibrinogen,  150. 

in  blood,  148,  158. 
Fibro-cartilage,  elastic,  41. 

intervertebral,  66. 

white,  40. 

yeUow,  41. 
Fibrous  tissue,  35. 
Fibula,  78. 

Filiform  papUlae,  412. 
FimbrijE  of  Fallopian  tube,  444. 
Fissure,  52. 
Flexion,  87. 

Flexor  muscles,  of  forearm,  112. 
Foetal  circulation,  224,  231. 
Follicles,  simple,  267. 
Fontanelles  of  skull,  59. 
Food,  action  of  bile  upon,  298. 
of  gastric  juice  upon,  295. 
of  pancreatic  juice  upon,  297. 
of  saliva  upon,  291. 

amount  necessarj%  312,  321. 

changes  undergone  by,  in  large  intes- 
tine, 299.  306. 
in  mouth,  291,  304. 
in  small  intestine,  296,  305. 
in  stomach,  293,  305. 

classification  of,  286,  302. 

definition  of,  286. 

heat  value  of,  312,  321. 
Foot,  bones  of,  79,  80. 

digits  of,  80. 

dorsum  of,  arterj'  of,  200. 

phalanges  of,  80. 
Foramen  magnum,  53. 

of  bone,  52. 

of  Monro,  392. 

ovale,  166,  224. 
Forearm,  muscles  of,  112. 
Formula,  chemical,  6. 
Fossa,  glenoid,  57. 

nasal,  250. 

of  bone,  52. 
Fovea  centralis,  429. 


512 


INDEX 


Fracture,  42. 

green-stick,  42. 
Frontal  bone,  54. 

lobe  of  cerebrum,  391. 

sinuses,  55. 
Fungiform  papillae,  412. 
Funiculi,  of  nerve  fibres,  374. 

Gall-bladder,  278,  285.     ' 

function  of,  279. 
Ganglia,  collateral,  376,  405. 

on  spinal  nerves,  381. 

sumpathetie,  376,  405. 

terminal,  376,  405. 

vertebral,  376,  404. 
Gases  in  blood,  147,  148,  158. 
Gaster,  281 ;  and  see  Stomach. 
Gastric,  artery,  194. 

juice,  294. 

lipase,  295. 

secretin,  294. 
Gastrin,  294. 
Gastrocnemius,  118. 
Generative  organs,  female,  442,  463. 
external,  449,  463. 
function  of,  451. 
internal,  442,  463. 
physiology  of,  465. 

male,  457,  466. 
Gcnesiology,  definition  of,  14. 
Gcnioglossus,  101. 
Germinative  layer  of  skin,  344. 
Gigantism,  317. 
Ginglymus,  88. 
Gladiolus,  69. 
Glands,  134. 

accessorj-  thyroid,  314. 

adrenal,  316. 

Bartholin's,  451. 

Brunner's,  268. 

carotid,  317,  322. 

ceruminous,  350. 

classification  of,  135. 

coccygeal,  317,  322. 

compound,  135. 

Cowper's,  468. 

development  of,  135. 

ductless,  136,  313,  321. 

duodenal,  268. 

intestinal,  237. 

lacrimal,  422. 

mammary,  453,  465. 

Meibomian,  422. 

of  stomach,  265. 

of  \'xilva,  451. 

parath>Toid,  315. 

parotid,  257. 

prostate,  468. 

salivary,  257. 

sebaceous,  349,  360. 

secreting,  135. 

simple,  135. 

sublingual,  257. 


Glands  —  continued 

submaxillary,  257. 

summary  of,  139. 

suprarenal,  316. 

sweat,  350,  360. 

tarsal,  422. 

thynuis,  315. 

thyroid,  313. 

urethral,  451. 

vulvo-vaginal,  451. 
Glenoid  cavity,  71. 

fossa,  57. 
Glisson's  capsule,  278. 
Globulins,  148. 
Glomerulus,  327. 
Glossopharyngeal  nerve,  397. 
Glottis,  236. 
Glucose,  in  urine,  336. 
Gluten,  as  food,  287. 
Gluteus  maximus,  115. 

medius,  115. 

minimus,  115. 
Glycogenic  function  of  liver,  278. 
Glycosuria,  336. 
Goitre,  315. 

exophthalmic,  315. 
"Goose  flesh,"  348. 
Graafian  follicles,  443,  463. 
Green-stick  fracture,  42. 
Gristle,  40  ;   and  see  Cartilage. 
Gullet,  261,  281. 

Haemoglobin,  143. 
Hairs,  347,  360. 
Hamstring  muscles,  1 16. 
Hand,  body  of,  74. 

bones  of,  74. 
Haversian,  canal,  44,  48. 

system,  44,  48. 
Head,  52. 

bones  of,  53. 

muscles  of,  95. 

of  bone,  52. 
Hearing,  414.  420,  434. 
Heart,  161,  180. 

auricle,  164. 

-beat,  216,  228. 
cause  of,  216. 

blood  supply  of,  168,  181. 

cavities  of,  164,  180. 

chordae  tendineae,  166. 

murmurs,  216. 

muscle  fibres  of,  162. 

nerve  supply  of,  168,  181,  217. 

orifices  of,  165,  180. 

papillary  muscles,  166. 

sounds  of,  216,  228. 
causes  of,  228. 

summary,  180. 

valves  of,  166,  181,  218. 
bicuspid,  J 66,  181. 
function  of,  167,  168. 
influence  of.^n  circulation,  218. 


INDEX 


513 


Heaxt  —  continued 
mitral,  166,  181. 
semilunar,  167,  181. 
tricuspid,  166,  181. 

ventricles,  164. 
Heat,  bodily,  352. 

centres  for,  355. 

distribution  of,  353. 

loss  of,  353,  361. 

production  of,  352. 

regulation  of,  354,  355,  361. 

variation  in,  357. 

where  produced,  352,  361. 
Heel  bone,  80. 
Hemophilia,  150,  159. 
Hemorrhage,  regeneration  of  blood  after, 

152,  159. 
Hemorrhoidal  artery,  superior,  195. 
Hepatic,  artery,  277. 

cells,  276. 

duet,  277. 

flexure,  270. 

vein,  277. 
Hernia,  109. 
Hiccough,  249. 
Highnaore,  antrum  of,  63. 
Hip,  bones  of,  74. 
Hippuric  acid,  336. 
Hormones,  137. 
Humerus,  71. 
Humor,  aqueous,  429,  440. 

vitreous,  430,  440. 
Hunger,  409,  433. 
Hyaline  cartUage,  40. 
Hyaloid  membrane,  430. 
Hydrate,  8. 
Hydration,  8. 

Hydrochloric  acid  in  gastric  juice,  295. 
Hydrolysis,  8,  29C. 
Hymen,   451. 

imperforate,  451. 
Hyoid  bone,  63. 
Hypermetropia,  431,  441. 
Hyperpncca,  247. 
Hypochondriac     regions     of     abdomen, 

262. 
Hypogastric,  artery,  197. 

region  of  abdomen,  262. 
Hypoglossal  nerve,  397. 
Hypophysis,  316,  322. 

Iced  food  or  drinks  injurious,  292. 

Ileo-csecal  valve,  270. 

Ileum,  266. 

Iliac,  arteries,  197,  198,  212. 

regions  of  abdomen,  262. 

veins,  207,  213. 
Iliopectineal  line,  76. 
Ilium,  75. 

Images,  inversion  of,  432. 
Immune  bodies,  in  blood,  149,  158. 
Impregnation,  460,  468. 

site  of,  461. 

2l 


Incisor  teeth,  259. 

Incus,  416. 

Indican,  in  urine,  337. 

Inferior  maxillary  nerve,  396. 

turbinated  bones,  60. 
Inflanimation,    circulatory    changes    in, 

145,  157. 
Infundibulum  of  lungs,  240. 
Infusion,  intravenous,  152,  160. 
Inguinal  canal,  109. 

ligament,  107. 

regions  of  abdomen,  262. 
Inhibition,  366. 

Inhibitory  nerve  fibres,  372,  403. 
Innominate  artery,  190. 

vein,  205,  212. 
Inorganic  compounds,  5. 
Inosculation  of  arteries,  185. 
Insalivation,  291. 
Inspiration,  242,  252. 
Intercellular  substance,  25. 
Intercentral  neurones  and  relays,  375. 
Intercostal  arteries,  193. 

muscles,  105. 
Interepithelial  arborizations,  369. 
Interlobular  veins,  276. 
Internal,  17. 

oblique  muscle  of  abdomen,  107. 

secretions,  313. 
in  blood,  149,  158. 
Intervertebral  disks,  66. 
Intestinal  digestion,  305. 

glands,  237. 

juice,  298. 
Intestine,    discharge    of   waste   matters 
from,  325. 

large,  270  ;   and  see   Large  intestine. 

small,  265  ;   and  see  Small  intestine. 

thick,  270  ;   and  see  Large  intestine. 

thin,  265  ;    and  see  Small  intestine. 
Intralobular  veins,  277. 
Intravenous  infusion,  152,  160. 
Inversion  of  images,  432. 
Iris,  426,  440. 
Irritability,  91. 
Ischium,  75. 
Island  of  Reil,  391. 
Islands  of  Langerhans,  273. 

Jejunum,  266. 
Joints,  82. 

ball-and-socket,  86. 

classification  of,  82. 

condyloid,  86. 

freely  movable,  85. 

gliding,  85. 

hinge,  86. 

immovable,  82. 

movements  of,  87. 

pivot,  86. 

reciprocal  reception,  88. 

saddle,  86. 

shghtly  movable,  84. 


514 


INDEX 


Joints  —  continued 

summary  of,  87. 

sutures,  82. 
Jugular  veins,  201,  212. 

Karj-okinesis,  24. 
Katabolism,  23. 
Kidneys,  326,  339. 

blood  supply  of,  327,  339. 

calyces,  339. 

capsule,  326,  327. 

function  of,  330,  340. 

glomerulus,  327,  329. 

Malpighian  corpuscles,  327,  339. 

matters  eliminated  by,  325. 

nerves  of,  329^  340. 

papilltB,  327. 

pelvis,  326. 

pyramids,  327. 

structure,  325,  328. 

supports,  326. 

uriniferous  tubules,  327,  339. 
Kinetic  theory,  10. 
Knee-cap,  77. 

Labia  majora,  450. 

minora,  450. 
Labyrinth,  417,  436. 
bony,  417,  436. 
membranous,  417,  436. 
Lacrimal  apparatus,  422,  438. 
bones,  61. 
gland,  422. 
sac,  423. 
Lacteals,  175,  176,  182. 
Lactose,  456. 
Lacunx'  of  bone,  44. 
Laraclhe  of  bone,  43. 
Langerhans,  islands  of,  273. 
Language,  basis  of,  394. 
Large  intestine,  270,  282. 
action  of  bacteria  in,  300. 
changes  undergone  by  food  in,  299. 
coats  of,  271. 
divisions  of,  270. 
functions  of,  271. 
movements  of,  299. 
secretion  of,  299. 
Larj'nx,  250. 
Lateral,  17. 
Latissimus  dorsi,  103. 
Laughing,  249. 
Leg,  bones  of,  74. 
Legumin,  287. 
Leucocytes,  i44. 
Leucocytosis,  144. 
Leucopenia,  144. 
Levatores  costarum,  105. 
Levator  palpebrse  superioris,  99,  422. 
Lieberkiihn,  crypts  or  follicles  of,  267. 
Ligamenta  flava,  37,  67. 
Ligaments,  37. 
annular,  118. 


Ligaments  —  continued 

inguinal,  107. 

of  uterus,  447,  465. 
Ligamentum  nuchae,  102. 
Light,  perception  of,  429. 

rays  of,  in  hypermetropic  eye,  431,  432, 
in  myopic  eye,  431,  432. 
in  normal  eye,  431,  432. 
Limbs,  20. 
Linea  alba,  108. 
Lipase,  295,  297. 
Liver,  273,  283. 

discharge  of  waste  matters  by,  325. 

fissures,  274. 

functions  of,  278. 

ligaments,  273. 

lobes,  275. 

loVmles  of,  275. 

lymphatics,  278. 

minute  anatomy,  275. 

nerves,  278. 

vessels,  295. 
Localization  of  brain  function,  393. 
Lower  extremities,  bones  of,  74. 

muscles  of,  112,  125. 
Lower  jawbone,  63. 
Lumbar  arteries,  197. 

fascia,  107. 

regions  of  abdomen,  262. 
Lungs,  230,  251. 

anatomy  of,  240. 

blood-vessels  of,  240. 

capacity  of,  245,  253. 

infundibulum  of,  240. 

lobule  of,  241. 

matters  eliminated  by,  325. 

nerves  of,  240. 
Lymph,  141,  153,  160,  223,  230. 

differences  between  blood  and,  153. 

flow  of,  223,  230. 

formation  of,  223,  230. 

function,  153,  160. 

interchange  between  blood  and,  154. 

sources  of,  153,  160. 
Lymphatic  duct,  right,  174,  182. 

part  drained  by,  173,  175. 
Lymphatics,  172,  174,  182. 

classification  of,  175. 

function  of,  176. 
Lymphatic  vessels,  172,  174,  182;    and 

see  Lymphatics. 
Lymph  nodes,  172,  176,  182,  183. 

function  of,  178,  183. 

location  of,  178,  183. 
Lymph  nodules,   aggregated,  of   Peyer, 
269. 
solitary,  269. 
Lymphocytes,  144. 
Lymphoid  tissue,  40. 
Lymph  spaces,  172,  174,  182. 

Macula  lutea,  429. 
Malar  bone,  61. 


INDEX 


515 


Malleolus,  external,  78. 

inner,  78. 

lateral,  78. 

medial,  78. 
Malleus,  416. 
Malpighian  corpuscles,  of  kidney,  327, 339. 

of  spleen,  318. 
Malpighian  layer  of  skin,  344,  359. 
Mammary  glands,  453,  465. 
Mandible,  63. 
Manubrium,  68. 
Marrow  of  bone,  44,  48. 
Mastication,  291. 

muscles  of,  99,  121. 
Mastoid,  cells,  56,  416. 

process,  56. 
Matter,  changes  in,  4. 

definition  of,  3. 

forms  of,  3. 
Maxilla,  62. 

Maxillary  bones,  62,  63. 
Measurements,  table  of,  25. 
Meatus,  external  auditory,  414. 

of  bone,  52. 
Medial,  17. 
Median  line,  17. 
Mediastinal  arteries,  193. 
Mediastinum,  242,  252. 
Medulla  oblongata,  385,  406. 
centres  in,  386. 
functions  of,  385,  406. 
Medullary  canal  of  bone,  50. 

sheath,  367. 
MeduUated  nerve-fibres,  367. 
Meibomian  glands,  422. 
Meissner's  corpuscles,  410. 
Membrana  tympani,  416,  435. 
Membrane,  or  membranes,  37,  127. 

basement,  127. 

classification  of,  127. 

cutaneous,  134. 

hyaloid,  430. 

mucous,  130 ;    and  see  Mucous  mem- 
brane. 

pituitary,  234. 

Schneiderian,  234. 

serous,  127  ;  and  see  Serous  membranes. 

summary  of,  137. 

synovial,  129  ;   and  see  Synovial  mem- 
branes. 
Meninges  of  brain,  384. 

of  spinal  cord,  378. 
Menopause,  452. 
Menstruation,    452,  465. 

and  ovulation,  453,  465. 

changes  in  connection  with,  452. 

purpose  of,  453. 
Mesenteric  artery,  inferior,  195. 

superior,  194. 
Mesentery,  255. 
Mesoderm,  27,  33. 
Metabolic  changes,  307. 

factors  promoting,  308. 


Metabolism,  23,  307,  319. 

changes  occurring  in,  307,  308. 

factors  promoting,  308. 

functions  of,  308. 

of  carbohydrates,  309,  320. 

of  fats,  308,  320. 

of  proteins,  310,  320. 
Metacarpus,  bones  of,  74. 
Metatarsus,  80. 
Micturition,  332,  341. 

involuntary,  333. 
Milk,  composition  of,  456,  466. 

human  and  cow's,  456. 

secretion  of,  455,  456,  466. 
Milk  sugar,  456. 
Mineral  matter  as  food,  302. 
Mixtures,  4. 
Modiolus,  419. 
Molar  teeth,  260. 
Molecule,  3,  6. 
Moleschott's  diet,  312. 
Monosaccharids,  288. 
Monro,  foramen  of,  392. 
Mons  Veneris,  449. 
Motor  areas  of  brain,  393,  407. 

nerve  fibres,  371,  372,  403. 

plates,  370. 

tracts  of  spinal  cord,  380. 
Motor-oculi  nerve,  396. 
Mouth,  234,  255,  279 ;    and  see  Buccal 
cavity. 

changes  undergone  by  food  in,   291, 
304. 

digestion  in,  291. 
Mucous  membranes,  130. 

function  of,  133. 

gastro-pulmonary,  130. 

genito-urinary,  131. 

structure  of,  131. 

summary  of,  138. 
Mucus,  140. 
Muscle,  or  muscles,  89. 

adductors  of  thigh,  115. 

arrector,  of  hairs,  348. 

attachment  of,  to  skeleton,  94. 

automaticity  of,  93. 

biceps,  of  arm.  111. 
of  leg,  115. 

blood  vessels  of,  92. 

buccinator,  100. 

cardiac,  91,  162. 

characteristics  of,  91. 

classification  of,  89,  119. 

contractility  of,  91,  93,  120. 

contractor  of  pupQ,  426. 

deltoid,  110. 

diaphragm,  105. 

dilator  of  pupil,  427. 

elasticity  of,  92. 

extensibility  of,  92. 

extensors  of  forearm,  112. 

external  oblique,  of  abdomen,  107. 

fatigue  of,  94. 


olG 


INDEX 


Muscle,  or  muscles  —  continued 
fibres,  90. 

of  heart,  1G2. 
flexors  of  forearm,  112. 
gastrocnemius,  118. 
genioglossus,  101. 
glutei,  114. 
gluteus,  maximus,  115. 

medius,  115. 

minimus,  115. 
gracilis,  115. 
hamstring,  116. 
iliacus,  114. 

inferior  oblique,  of  eyeball,  98. 
insertion  of,  95. 
intercostals,  105. 

internal  oblique,  of  abdomen,  107. 
involuntary,  90. 
irritability  of,  91. 
latissimus  dorsi,  103. 
levatores  costarum,  105. 
levator  palpebrre  superioris,  99,  422. 
names  of,  95. 
nerves  of,  92. 
non-striated,  90. 
occipito-frontalis,  96. 
of  abdomen,  102,  107,  123. 

action  of,  109. 
of  arm.  110. 
of  back,  102,  122. 
of  chest,  102,  103,  123. 
of  expression,  100,  122. 
of  eyeball,  97,  423,  438. 
of  face,  95,  97. 
of  forearm,  110,  112. 
of  head,  95. 

of  lower  extremity,  112,  125. 
of  mastication,  99,  121. 
of  neck,  95,  101,  122. 
of  orbit,  97,  121. 
of  shoulder,  1 10. 
of  thorax,  102,  105.  123. 
of  tongue,  95,  101,  122. 
of  trunk,  102. 

of  upper  extremity,  109,  124. 
orbicularis  oris,  100. 

palpebrarum,  422. 
orbital,  97. 
origin  of,  95. 
pectoral,  103. 
pectoral  is  major,  103. 

minor,  105. 
plain,  90. 
platysma,  101. 
posterior  femoral,  116. 
pronators,  of  forearm,  112. 
properties  of,  91. 
psoas  magnus,  113. 
quadriceps  extensor,  116. 
recti,  of  eyeball,  97. 
rectus  abdominis,  108. 

femoris,  117. 
sartorius,  115. 


Muscle,  or  muscles  —  continued 

semimembranosus,  115. 

semitcndino.sus,  115. 

skeletal,  89,  94. 

soleus,  118. 

sterno-cleido-mastoid,  101. 

stimuli  of,  91. 

striated,  89. 

striped,  89. 

styloglossus,  101. 

summary,  119. 

superior  oblique,  of  eyeball,  97. 

supinators,  of  forearm,  112. 

tables  of,  121  to  126. 

tetanus  of,  94. 

tonicity  of,  92. 

transversalis,  108. 

trapezius,  102. 

triceps.  111. 

varieties  of,  89. 

vastus,  extcrnus,  117. 
intermedius,  117. 
internus,  117. 

visceral,  90. 

voluntary,  90. 
Muscular  contractility,  91. 

sense,  409,  433. 

system,  26,  32. 

tissue,  89  ;   and  see  Muscle. 
Muscularis  mucosse,  132. 
Myelin  sheath,  367. 
Myocardium,  162. 
Myology,  definition  of,  14. 
Myopia,  431,  441. 
Myxoedema,  314. 

Nails,  347,  360. 
Nasal  bones,  60. 

breathing,  advantages  of,  234,  250. 
cavities,  19,  20,  234.  250. 
duct,  423. 
fossae,  233,  250. 
Neck,  muscles  of,  95.  101,  122. 
Nerve,  or  nerves,  abducens,  396. 
auditory,  397,  419,  436. 
-cell,  364,  402. 
centres,  374,  404. 
cerebrospinal,  363. 
cochlear,  419,  436. 
cranial,  364,  395. 
degeneration  of,  382. 
-endings,  368.  403. 

reaction  of.  373. 
facial.  396. 
-fibres,  367,  402. 

afferent,  371,  372,  403. 

classification  of,  371,  403. 

decussation  of,  385. 

efferent,  371,  372,  403. 

excitatory,  372,  403. 

funiculi  of,  374. 
•  inhibitory,  372,  403. 

meduUated,  367. 


INDEX 


517 


Nerve  fibres  —  continued 
motor,  371,  372,  403. 
non-medullated,  368. 
reflex,  372,  403. 
secretory,  372,  403. 
sensorj',  371,  372,  403. 
ganglia,  376,  381,  404. 
glossopharyngeal,  397. 
hypoglossal,  397. 
impulse,  403. 

direction  of,  371. 
identity  of,  372. 
nature  of,  370. 
speed  of,  373,  403. 
stimulus  necessary  for,  399. 
inferior  maxillary,  396. 
mixed,  380. 
motor  oculi,  396. 
of  eye,  423. 
of  nose,  414. 
of  tongue,  412. 
olfactory,  396. 
ophthalmic,  396. 
optic,  396. 
pathetic,  396. 
peripheral,  383. 
plexus,  370,  377. 
pneumogastric,  397. 
processes,  366. 
regeneration  of,  382. 
spinal,  364,  380,  406. 
spinal  accessory,  397. 
stimulation,  artificial,  370. 

physiological,  371. 
superior  maxillary-,  396. 
tissue,  properties  of,  364,  402. 

varieties  of,  404. 
trifacial,  396. 
trochlear,  396. 
trunks,  404. 

formation  of,  373. 
vasoconstrictor,  169,  181,  378. 
vasodilator,  169,  181,  378. 
vasomotor,  169,  181,  378. 
vestibular,  420,  436. 
Nervous  system,  26,  32,  363. 
autonomic,  376. 
central,  363. 

interdependence  of,  377. 
divisions  of,  363,  401. 
functions  of,  363,  401. 
gray  matter  of,  373. 
parts  of,  363,  401. 
regulation  of  bodily  heat  by,  354. 
sympathetic,  364. 
white  matter  of,  373. 
Neuraxon,  366. 
Neurilemma,  367. 
Neuroglia,  364,  373,  404. 
Neurology,  definition  of,  14. 
Neurones,  364,  365,  402. 

intercentral,  375. 
Neutralization,  8. 


I  Nipple,  454. 

I  Nitrogen  equilibrium,  311,  320. 
Nodes  of  Ranvier,  402. 
Non-medullated  nerve-fibre,  368 
Nose,  232,  250. 
external,  232,  250. 
functions  of,  250. 
internal,  250. 
nerves  of,  414. 

sinuses  communicating  with,  234,  250. 
Nucleus  of  cell,  22. 

Obesity,  causes  of,  309,  320. 
Oblique  muscles,  of  eyeball,  97. 
Occipital  bone,  53. 

lobe  of  cerebrum,  391. 
Occipito-frontalis,  96. 
Odontoid  process,  66. 
Odors,  413,  4.34. 
(Edema,  224,  231. 
CEsophageal  arteries,  193. 
(Esophagus,  261,  281. 
Olecranon  process,  72. 
Olfactory  bulb,  414. 

nerve,  414. 
Omentum,  255,  264. 
Ophthalmic  nerve,  396. 
Opsonins,  145,  158. 
Optic  chiasm,  429. 
foramen,  439. 
nerve,  396,  423. 
Orbicularis  oris,  100. 
Orbit,  423,  439. 

bones  of,  423,  439'. 
Orbital  cavity,  19,  20. 

muscles,  97,  423,  438. 
Organ,  25,  32. 

of  Corti,  419,  436. 
Organic  compounds,  5. 
Organules,  363,  369. 
Os  coxae,  74. 
Osmosis,  10,  154. 
Osmotic  pressure,  11. 
Osseous  tissue,  42  ;  and  see  Bone. 
Ossicles  of  ear,  416,  435. 
Osteology,  definition  of,  14. 
Otoliths,  418. 
Ovarian  arteries,  197. 
Ovaries,  442,  463. 
Overeating,  efifects  of,  321. 
Oviducts,  444,  464. 
0\-ulation,  452,  465. 

and  menstruation,  453,  465. 
0\-um,  443,  460,  408. 
lecundated,  development  of,  468. 
segmentation  of,  461. 
Oxidation,  8. 
Oxide,  7. 
acid,  7. 
basic,  7. 
Oxyhaemoglobin,  143. 

Pacini,  corpuscles  of,  370,  459. 
Pain,  409,  433. 


518 


INDEX 


Filiate,  256. 
Palate  bones,  61. 
Palatine  arches,  256. 
Palmar  arch,  deep,  193. 
superficial,  193. 

fascia,  37. 
Pancreas,  272,  283. 

functions  of,  273. 

structure  of,  272. 
Pancreatic  juice,  297. 

action  of,  upon  food,  297. 

secretion  of,  296. 
Papillae  of  skin,  345. 

of  tongue,  411,  434. 

on  mucous  membrane,  133. 
Papillary  muscles,  166. 
Paraglobulin,  14>S,  158. 
Parathyroids,  315,  322. 
Parietal  bones,  54. 

lobe  of  cerebrum,  391. 
Parotid  glands,  257. 
Patella,  77. 
Pathetic  nerve,  396. 
Pavement  epithelium,  28. 
Pectoralis  major,  103. 

minor,  105. 
Pectoral  muscles,  103. 
Pelvic  cavity,  20. 
Pehns,  75. 

brim  of,  76. 

false,  76. 

female,  75,  76. 

inlet  of,  76. 

male,  76. 

outlet  of,  76. 

strait  of,  76. 

true,  76. 
Penis,  459,  467. 
Pepsin,  295. 

Pericardial  arteries,  193. 
Pericardium,  128,  163. 
Perichondrium,  42. 
Perilj-mph,  418. 
'  Perineum,  451. 
Periosteum,  44,  48. 

function  of,  in  growth  of  bone,  46. 
Periphery,  17. 
Peristalsis,  293,  296. 
Peritoneum,  128,  255. 
Peroneal  artery,  200. 
Perspiration,  350,  360. 

insensible,  351. 

quantity,  ,351.  .360. 

sensible.  351. 
Peyer's  glands,  or  patches,  269. 
Phagocytosis.  145. 
Phalanges,  of  foot,  80. 

of  hand,  74. 
Pharynx,  234,  260.  280. 
Phrenic  arteries,  197. 
Physical  change,  4. 

sciences,  3. 
Physics.  3. 


Physiological  saline  solution,  152. 
Physiology,  definition  of,  14. 
Pia  mater,  384. 
Pinna,  414,  435. 
Pituitary  body,  316. 

membrane,  234. 
Placenta,  224. 
Plantar,  arch,  200. 

arteries,  200. 

fascia,  37. 
Plasma,  -142,  147,  157. 
Platysma,  101. 
Pleura,  128,  242,  252. 
Plexus,  arterial,  185. 

ner\'e,  370,  377. 
Pneumogastric  nerve,  397. 
Polysaccharids,  288. 
Pons  Varolii,  387,  406. 

functions  of,  388,  406. 
Popliteal  artery,  200. 
Portal  system,  210. 

vein,  276. 
Position,  anatomical,  14. 
Poupart's  ligament,  107. 
Premolar  teeth,  259. 
Presbyopia,  432,  441. 
Pressure  sensation,  410,  433. 
Prickle  cells,  30. 
Process,  acromion,  71. 

ensiform,  69. 

mastoid,  56. 

nerve  cell,  366. 

odontoid,  66. 

of  bone,  52. 

olecranon,  72. 

xiphoid,  69. 
Pronator  muscles,  of  forearm,  112. 
Prostate,  460,  468. 
Protecting  sheaths,  367.    . 
Proteins,  adequate,  311. 

as  food,  287,  302. 

cla.ssification  of,  311,  320. 

digestion  of,  290. 

function  of,  311. 

inadequate,  311. 

in  blood,  147,  158. 

metabolism  of,  310,  311. 
Prothrombin,  150. 
Protoplasm,  21. 
Proximal,  17. 
Psoas  magnus,  113. 
Ptyalin,  292. 
Puberty,  in  female,  451,  465. 

in  male,  460,  468. 
Pubes,  75. 
Pulmonary,  artery,  185. 

system,  185,  210. 

veins,  187. 
Pulse,  221,  2.30. 

frequency  of,  222,  230. 

locations  where  it  may   be  felt,  222, 
230. 

points  to  note,  in  feeling,  222,  230. 


INDEX 


519 


Pulse  —  continued 

ratio  of,  to  respiration,  223. 

variations  in,  223. 
Pupil,  of  eye,  426,  440. 

contraction  of,  426. 

dilatation,  427. 
Pus,  in  urine,  338. 
Pylorus,  263. 

Quadriceps  extensor  muscle,  116. 

Rachitis,  bones  in,  43. 
Radial  artery,  193. 

veins,  202. 
Radius,  72. 
Rales,  245. 

Rami  communicantes,  376,  377. 
Ranke's  diet,  312. 
Ranvier,  nodes  of,  368,  402. 
Receptaculum  chyli,  174. 
Reciprocal  reception,  88. 
Recti  muscles,  of  eyeball,  97. 
Rectum,  271. 
Rectus  abdominis,  108. 

femoris,  117. 
Reflex  act,  397,  407.  • 

arc,  398. 

nerve  fibres,  372,  403. 
Refracting  media,  439. 
Refraction,  430,  441. 
Refractive  apparatus,  430,  440. 
Regeneration  of  nerves,  382. 
Reil,  island  of,  391. 
Relays,  375. 
Relay  station,  369. 
Remak,  fibres  of,  368. 
Renal  arteries,  195. 

corpuscles,  327,  339. 
Renuin,  295. 
Reproduction,  460,  468. 
Reserve  air,  246. 
Residual  air,  246,  253. 
Respiration,  242,  252. 

abnormal  types  of,  247,  253. 

cause  of,  243,  252. 

cause  of  first,  244,  253. 

Cheyne-Stokes,  248. 

control  of,  243. 

effect  of,  on  air,  253. 

effect  of,  on  blood,  245,  253. 

effect  of,  on  blood  pressure,  220. 

effect  of,  on  lymph  flow,  224. 

external,  242,  252. 

frequency  of,  245. 

function  of,  242,  252. 

heat  regulation  by,  354. 

internal,  242,  252. 

cedematous,  248. 

rate  of,  253. 

ratio  of,  to  pulse,  223,  253. 
Respiratory  centre,  243,  252. 
reflex  stimulation  of,  244. 

movements,  modified,  249. 


Respiratory  —  continued 

sounds,  245. 

system,  26,  32,  232,  234. 
Restiform  bodies,  386. 
Reticular  tissue,  39. 
Retiform  tissue,  39. 
Retina,  440. 

layers  of,  440. 
Ribs,  69. 

Rickets,  bones  in,  43. 
Rods  and  cones,  428. 
Rotation,  87. 

Round  ligaments,  of  uterus,  448. 
Rugae,  of  stomach,  265. 

of  mucous  membrane,  133. 

of  vagina,  449. 
Rupture,  109. 

Saccule,  418,  436. 

Sacral  artery,  middle,  197. 

Sacrum,  68, 

Saline  solution,  physiological,  152. 

Saliva,  291. 

functions  of,  292. 

secretion  of,  291. 
Salivary  glands,  257,  280. 
Salt,  7. 

as  food,  287. 

in  blood,  147,  148,  158. 
Saphenous  veins,  external,  206. 

internal,  205. 

long,  205. 

short,  205. 
Saponification,  289. 
Sarcolemma,  90. 
Sartorius,  115. 
Scapula,  71. 
Scarpa's  triangle,  200. 
Schneiderian  membrane,  234. 
Sclera,  425,  439. 
Scrotum,  459,  467. 
Sebaceous  glands,  349,  360. 
Sebum,  349. 
Secretin,  gastric,  294. 
Secreting  glands,  135. 
Secretions,  136. 

external,  136. 

internal,  136,  313. 

summary  of,  139. 

table  of,  140. 
Secretory  nerve  fibres,  372,  403. 
Segmentation  of  ovum,  461. 
Semen,  460,  468. 
Semicircular  canals,  419,  436. 
Semilunar  valves,  167,  181. 
Semimembranosus,  115. 
Seminal  vesicles,  458,  467. 
Semitendinosus,  115. 
Sensations,  408,  433  ;   and  see  Senses. 

classification  of,  408,  433. 

definition  of,  408. 

organs  necessary  for,  408,  433. 

where  interpreted,  408. 


520 


INDEX 


Sense  or  senses ;  and  see  Sensations. 

areas  of  brain,  394,  407. 

exterior.  409,  433. 

external,  409,  433. 

interior,  408,  433. 

internal,  408,  433. 

mu.scular,  409. 

of  e(|uilihrium,  420,  437. 

of  fatigue,  410. 

of  hearing,  420. 

of  hunger,  409. 

of  pain,  409. 

of  pressure,  410,  433. 

of  sight,  421,  429,  437. 

of  smell,  413. 

of  taste,  411. 

of  temperature,  410,  433. 

of  thirst,  409. 

of  touch,  410. 

visceral,  410. 
Sensory  area  of  brain,  394,  407. 

fibres,  371,  372,  403. 

tracts  of  spinal  cord,  380. 
Serous  sacs,  176. 

membranes,  127,  137. 
classes  of,  128. 
function  of,  128. 
of  capsule  of  Tenon,  128. 
of  cavities,  128. 
of  cerebrospinal  axis,  128. 
of  vascular  system,  128. 
proper,  128. 

secretion,  138. 
Serum,  159. 

albumin,  148,  158. 
Sesamoid  bones,  49. 
Sharpcy,  fibres  of,  44. 
Sheath,  myelin,  367. 
Shin-bone,  78. 
Shoulder  blade,  71. 

muscles  of,  110. 
Sighing,  249. 
Sight,  421,  429,  437. 
Sigmoid  flexure,  270. 
Simple  epithelium,  28. 
Sinews,  37. 

Sinuses  communicating  with  nose,  234, 
250. 

of  bone,  52. 

of  head,  59. 

venus,  of  skull,  201. 
Sinusitis,  59. 
Skeletal  muscles,  89,  94. 
Skeleton,  49. 

attachment  of  muscles  to,  89,  94. 

divisions  of,  52. 
Skin,  344,  359. 

appendages,  347.  359. 

blood-vessels  of,  346,  359. 

discharge  of  waste  matters  by,  325, 
.352. 

functions  of,  344,  352,  359. 

heat  regulation  by,  354. 


Skin  —  continued 
layers  of,  344,  359. 
nerves  of,  346,  359. 
summary,  359. 
Skull,  52. 

as  a  whole,  58. 
bones  of,  52. 
diploe  of,  58. 
Small  intestine,  265,  281. 
action  of  bacteria  in,  299. 
changes  undergone  by  food  in,  296. 
coats  of,  265. 
digestion  in,  295,  305. 
divisions  of,  265. 
functions  of,  269. 
glands  of,  267. 
lymph  nodules  of,  268. 
movements  of,  296. 
Smell,  413,  4.34. 

necessary  conditions  for.  413,  434. 
Sneezing,  249. 
Sobbing,  249. 
Soleus,  118. 

Solution,  physiological  saline,  152. 
Speaking,  249. 
Specific  gravity,  9. 
Speech  areas  in  brain,  394. 
Spermatic  arteries,  197. 

cord,  459,  467. 
Spermatozoon,  461,  468. 
Sphrnoidal  fissure,  439. 
Sphenoid  bone,  58. 
Spina  bifida,  68. 
Spinal-acce.ssory  nerve,  397. 
Spinal  canal,  18,  20,  391. 
cord,  378,  405. 

central  canal  of,  391. 
functions  of,  383,  405. 
membranes  of,  378,  405. 
section  of,  379. 
structure  of,  378,  405. 
tracts  of,  380. 
ganglia,  381. 
nerves,  364,  380,  406. 
degeneration  of,  382. 
distribution  of  terminal  branches  of, 

382. 
ganglion  on  posterior  root  of,  331. 
regeneration  of,  382. 
roots  of,  380. 
Spinous  processes,  of  bone,  52. 

of  ilium,  75. 
Splanchnology,  definition  of,  14. 
Spleen,  317,  .323. 
Splenic  artery,  194. 

flexure,  271. 
Sprain,  87. 
Stapes,  416. 

Starch,  action  of  saliva  on,  292. 
of  pancreatic  juice  on,  297. 
Steapsin,  297. 
Sterno-cleido-mastoid,  101. 
Sternum,  68. 


INDEX 


521 


Stimuli,  muscular,  91. 

nerve,  370,  371. 
Stomach,  263,  281. 

blood-vessels  of,  265. 

coats  of,  263. 

digestion  in,  293,  305. 

functions  of,  265. 

glands  of,  265. 

nerves  of,  265. 

peristaltic  action  of,  293. 
Stratified  epithelium,  30. 
Styloglossus,  101. 
Subarachnoid  space,  384. 
Subclavian  arteries,  192. 

veins,  204,  212. 
Sublingual  glands,  257. 
Subniaxillary  glands,  257 
Succus  entericus,  298. 
Sugar,  288. 

in  blood,  148,  158. 
Summation,  366. 
Superior  maxillary  nerve,  396. 
Supinator  muscles,  of  forearm,  112. 
Suprarenal  arteries,  196. 

capsules,  316,  322. 
Sutures,  82,  87. 

coronal,  82. 

frontal,  83. 

lambdoidal,  82. 

of  skull,  83,  84. 

sagittal,  83. 
Swallowing,  292. 

Sweat,  350 ;   and  see  Perspiration. 
Sweat-glands,  350,  360. 
Sylvius,  aqueduct  of,  392. 
Sympathetic  ganglia,  376,  405. 

system,  375,  401. 

interdependence  of,  377. 
Symphysis,  84,  88. 

pubis,  75. 
Synapse,  366,  402. 
Synarthroses,  82,  87. 
Synchondrosis,  83,  87. 
Syndcsmology,  definition  of,  14. 
Syndesmosis,  85,  88. 
Synovia,  129. 
Synovial  membranes,  129. 

function  of,  130. 
System,  26,  32. 
Systole,  216. 

Tactil.e  corpuscles,  370. 
Tarsal  cartilages,  421,  422. 

glands,  422. 
Tarsus,  bones  of,  78,  81. 

of  eye,  421,  422. 
Taste,  411,  434. 

buds,  411,  434. 

necessary  conditions  for,  411. 

organ  of,  411,  434. 

sense  of,  411,  434. 
Taste  buds,  411,  434. 
Tears,  438. 


Teeth,  257,  280. 

function  of,  260. 

permanent,  259. 

temporary,  259. 
Temperature,    necessary    for    digestion, 
292. 

sense  of,  410,  433. 

subnormal,  358. 

variations  in,  357,  358,  362. 
Temporal  bones,  55. 

mastoid  portion  of,  56. 
petrous  portion  of,  55. 
squamous  portion  of,  55. 

lobe  of  cerebrum,  391. 
Tendo  Achillis,  118. 
Tendons,  37,  94. 
Tenon,  capsule  of,  424. 
Terminal  ganglia,  376,  405. 
Testes,  457,  467. 

descent  of,  458. 
Testicle,  457  ;   and  see  Testes. 
Tetanus  of  muscle,  94. 
Thermogenetic  centres,  355. 
Thermolytic  centres,  355. 
Thermotactic  centres,  355. 
Thigh,  adductor  muscles  of,  115. 

bones  of,  77. 
Thirst,  409,  433. 
Thoracic  cavity,  19,  20. 

duct,  174,  182. 

parts  drained  by,  173,  )?4,  182. 
Thorax,  67,  68. 

bones  of,  68. 

muscles  of,  102,  105,  123. 
Thrombin,  150. 
Thrombus,  152,  159. 
Thymus,  315,  322. 
Thyroid,  accessory,  314. 

cartilage,  235. 

foramen,  75. 

gland,  313,  321. 
Tibia,  78. 
Tibial  arteries,  200. 

veins,  205. 
Tidal  air,  245. 
Tissue,  or  tissues,  25,  32. 

adenoid,  40. 

adipose,  38. 

areolar,  34. 

classification  of,  26,  32. 

connective,    34 ;    and  see  Connective 
tissues. 

definition  of,  25. 

elastic,  37. 

epithelial,  27  ;  and  see  Epithelial  tissue. 

fibrous,  35. 

lymphoid,  40. 

muscular,  89  ;   and  see  Muscle. 

nerve,  364  ;    and  see  Nerve. 

origin  of,  26,  32. 

osseous,  42  ;  and  see  Bone. 

reticular,  39. 

retiform,  39.  • 


522 


INDEX 


Tone,  arterial,  170. 
Tongue.  257,  280.  411.  434. 

muscles  of,  <J5.  101,  122. 

nerves  of,  412,  434. 

papillsDof,  411,  434. 

sensations  in,  413,  434. 
Tonicity  of  muscle,  92. 
Ton.sil.s,  256,  280. 
Torticolli.s,  102. 
Touch,  sense  of,  410. 
Trachea,  238,  251. 
Transitional  epithelium,  29. 
Transversalis,  108. 
Transverse  fissure  of  cerebrum,  390. 
Trapezius,  102. 
Triceps,  111. 

Tricuspid  valve,  166,  181. 
Trifacial  nerve,  396. 
Trochanters  of  femur,  77. 
Trochlear  nerve,  396. 
Trochoides,  88. 
Trunk,  bones  of,  64,  81. 

muscles  of,  102. 
Trypsin,  297. 
Tubercle  of  bone,  52. 
Tuberosity  of  bone,  52. 
Tunics  of  eye,  425,  439. 
Tympanum,  416. 

ossicles  of,  416. 

Ulna,  72. 

Ulnar  artery,  193. 

veins,  203. 
Umbilical  cord,  224. 

region  of  abdomen,  262. 
Under-nutrition,  321. 
Upper  extremities,  bones  of,  69,  81. 

muscles  of,  109,  124. 
Upper  jaw-bones,  62. 
Urea,  335,  342. 
Ureters,  331,  340. 
Urethra,  female,  332,  341. 

male,  459,  467. 
Urethral  glands,  451. 
Uric  acid,  335. 

Urinary  organs,  discharge  of  waste  mat- 
ters by,  325. 
Urine,  333,  342. 

abnormal  constituents  of,  336,  343. 

amount  of,  .334,  342. 

character  of,  333,  342. 

composition  of,  335. 

excretion  of,  332. 

retention  of,  3.33,  341. 

secretion  of,  330,  340. 

suppression  of,  333,  341. 

toxicity  of,  338. 
Uriniferous  tubules,  327,  339. 
Uterine  artery,  198. 
Uterus,  445,  465. 

blood  supply  of,  447,  465. 

cervix,  445. 

changes  in,  following  impregnation,  462. 


Uterus  —  continued 

coats  of,  446. 

divisions  of,  445,  465. 

function  of,  448. 

fundus,  445. 

ligaments  of,  447,  465. 

OS,  446. 

position  of,  447. 

structure  of,  446. 
Utricle  of  ear,  418,  436. 
U\'ula,  256. 

Vagina,  448,  464. 

Valve,  or  valves.  Eustachian,  168. 

ileo-caecal,  270. 

of  heart,  166,  181,  218. 

of  veins,  171. 
Vah-ulse  conniventes,  133,  266. 
Vasa  vasorum,  169,  181. 
Vascular  .system,  26,  32,  141,  182,  187, 
210. 

changes  in,  at  birth,  226,  231. 
Vas  deferens,  458,  467. 
Vasoconstrictor  nerv'es,  169,  181,  378. 
Vasodilator  nerves,  169,  181,  378. 
Vasomotor  centres,  378. 

nerves,  169,  181,  378. 
Vastus  externus,  117. 

iniermcdius,  117. 

internus,  117. 
Vein,  or  veins,  161,  171,  181,  200,  212. 

axillary,  204,  212. 

azygos,  207,  213. 

basilic,  204. 

cava,  inferior,  207. 
superior,  205. 

cephalic,  204. 

coronary,  201. 

deep,  200. 

femoral,  206,  213. 

hepatic,  277. 

iliac,  common,  207,  213. 
external,  207,  213. 
internal,  207,  213. 

influence  of,  on  circulation,  218. 

innominate,  205,  212. 

interlobular,  276. 

intralobular,  277. 

jugular,  external,  201,  212. 
internal,  201,  212. 

median,  203. 

popliteal,  205. 

portal,  213,  276. 

portal  system,  210,  213. 

pulmonary,  187. 

radial,  202. 

saphenous,  external,  206. 
internal,  205. 
long,  205. 
short,  205. 

structure  of,  171. 

subclavian,  205,  212. 

superficial,  200. 


INDEX 


523 


Vein,  or  veins  — -  continued 

systemic,  201. 

thoracic,  205. 

tibial,  anterior,  205. 
posterior,  205. 

ulnar,  203. 

valves  of,  171. 
Vena  cava  inferior,  207,  213. 

superior,  205,  213. 
Venae  comites,  200. 
Ventilation,  247,  253. 
Ventral  cavity,  18,  20. 

surface,  14. 
Ventricles,  of  brain,  391,  392,  407. 

of  heart,  164. 
Vermiform  appendix,  270. 
Vernix  caseosa,  350. 
Vertebrse,  64,  65. 

false,  65. 

number  of,  65. 

regions  of,  65. 

true,  65. 
Vertebral  artery,  192. 

column,  64. 

abnormal  conditions  of,  67. 
bones  of,  64,  65. 
curvatures  of,  65,  67. 
structure  of,  67. 

ganglia,  376,  404. 
Vesicles,  seminal,  458,  467. 
Vesicular  follicles  of  ovary,  443. 
Vestibular  nerve,  420,  436. 
Vestibule,  of  ear,  418,  436. 
Villi,  133,  267. 


Viscera,  17. 
Visceral  muscles,  90. 

sensations,  410,  433. 
Viscus,  17. 

Visual  apparatus,  437. 
Vital  capacity,  246. 

centres,  375. 
Vitreous  humor,  430,  440. 
Vocal  cords,  236. 
Voice,  237,  251. 

difference   between  that  of  male  and 
female,  238. 
Vomer;  60. 
Vomiting,  293. 
Vulva,  450. 

glands  of,  451. 
Vulvo-vaginal  glands,  451. 

Wandering  cells,  145. 

Waste  products,  148,  158,  324.  338. 

discharge  of,  325,  338. 
Water,  as  food,  286,  302. 
Wharton's  jelly,  224. 
Willis,  circle  of,  191. 
Windpipe,  238. 
Wisdom  teeth,  260. 
Wrist,  bones  of,  72,  73. 
Writer's  cramp,  94. 
Wry  neck,  102. 


Xiphoid  process,  69. 

Yawning,  249. 
Yellow  spot,  429. 


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training  schools  that  an  elementary  knowledge  of  chemistry  is  indispensable  if 
students  are  really  to  understand  what  is  taught  them  in  the  subjects  of  Maieria 
Medica  and  Dietetics.  This  has  rt-sulted  in  many  states  making  chemi>try  a 
required  study  and  it  is  rapidly  becoming  recognized,  in  an  increasing  number 
of  states,  as  a  necessary  part  of  the  course. 

Up  to  the  present,  no  textbook  on  elementary  chemi'.try  has  been  published 
distinctly  tor  nurses.  Dr.  Ottenberg  has,  therefore,  prepared  this  splcndiii  little 
book,  which  presents  the  subject,  for  the  course  in  training  schools,  with  s  m- 
plicity  and  thoroughness.  The  fault  of  the  elementary  textbooks  on  chemistry, 
previously  used  in  this  course  for  want  of  a  distinct  te.xt  for  nurses,  seems  to  lie 
in  the  fait  that  tliey  do  not  take  up  the  special  points  without  which  a  knowledge 
of  Dietetics  or  food  values  is  impossible,  while  the  more  advanced  te.xts  are 
entirely  too  difficult  for  nurses,  since  they  presuppose  an  amount  of  preliminary 
training  which  very  few  nurses  have. 

It  is  believed  that  Chemistry  for  Nurses  will  fill  a  definite  need,  as  pupil 
nurses  have  repeatedly  asked  for  a  text-book  to  answer  their  peculiar  require- 
ments. 

Bacteriology  for  Nurses 

Including  Schedule  for  Laboratory  Exercises,  etc. 
By   IS.^BEL   McISAAC 

Superintendent  United  States  Army  Norse  Corps;  Author  of  "  Hygiene  for  Nurses,"  etc 
Second  Edition.     Revised.     Cloth,  illustrated,  $  1.25 

This  is  a  completely  revised  edition  of  the  well-known  textbook  which  has, 
for  years,  been  ihe  only  book  written  distinctly  for  the  use  of  nurses,  and  much 
new  material  has  been  added.  The  author  has  carefully  confined  herself  to  the 
needs  of  the  c  ass  for  whom  it  is  intended  and  she  has  been  singularly  success- 
ful in  avoiding  unnecessary  digfression,  making  clear  the  practical  as  well  as  the 
theoretical. 

The  scheme  of  the  original  work  has  been  maintained.  There  are  chapters 
on  Structure,  Mode  of  Development,  and  Composition  of  Bacteria  ;  The  Effect 
of  Physical  and  Chemical  Agents  upon  Bacteria,  and  the  Kffects  of  Bacterial 
Growth;  The  Relations  of  Bacteiia  to  Disease;  Immunity;  Inflammation, 
Suppuration,  Pneumonia,  Epidemic Cerebro-Spinal  Meningitis;  Typhoid  Fever 
(Enteric  Fever)  ;  Asiatic  Cholera,  Relapsing  Fever;  Infectious  Diseases  of 
Unknown  Cause,  and  Bacteria  in  Air,  Soil,  Water,  and  Food. 


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NEW  AND  STANDARD  BOOKS  FOR  NURSES 


Hygiene  for  Nurses 


By  ISABEL  McISAAC 

Superintendent  U.  S.  Army  Nurse  Corps.  Formerly  Superintendent   of  the 

Illinois  Training  School  of  Nurses 

Cloth,  127710,  $1.25 

The  pages  of  this  book  are  full  of  just  the  information  that  every 
woman  in  charge  of  souls  and  bodies  needs.  The  chapters  on  food, 
ventilation,  sewage,  causes  and  dissemination  of  disease,  household, 
personal,  and  school  hygiene,  the  hygiene  of  occupation,  disinfection, 
etc.,  are  all  of  the  most  vital  interest  and  value  to  the  nurse. 

Primary  Nursing  Technique 

FOR  FIRST  YEAR  PUPIL  NURSES 

By  ISABEL  McISAAC 

Cloth,  127710,  $1.25 

A  valuable  and  thorough  book  for  nurses  starting  on  their  course 
of  study.  It  is  written  with  the  one  object  in  view  of  inculcating 
into  the  minds  of  its  readers  the  fact  that  an  accurate  knowledge  of 
the  human  body  is  the  first  essential  to  successful  nursing. 


Nursing  the  Insane 


By  CLARA   BARRUS 

Woman  Assistant  Physician  in  the  Middletown  State  Homeopathic  Hospital, 
Middletown,  N.Y. 

Cloth,  8vo,  $2.00 

This  is  an  illuminative,  sensible,  straightforward  book  covering  the 
various  features  of  the  nurse's  work  in  caring  for  the  insane.  There 
are  directions,  not  only  for  medical  and  clinical  care  of  the  insane, 
for  their  occupation  and  amusements,  with  directions  as  to  how  they 
may  be  moved,  but  above  all  there  are  some  very  interesting  chap- 
ters on  psychology,  so  that  the  nurse  may  appreciate  patients'  states 
of  mind  and  sympathize  with  their  peculiarities. 


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NEW  AND  STANDARD  BOOKS  FOR  NURSES 

The  Life  of  Florence  Nightingale 

WITH   PHOTOGRAVURE   PORTRAITS 

By  sir  EDWARD   COOK 

Two  vols.,  cloth,  8vo.  $7.jo 

"A  masterly  biography  which  not  only  puts  into  a  permanent 
record  her  whole-souled  devotion  and  humanity,  but  relates  the  his- 
tory of  one  of  the  greatest  and  most  fruitful  movements  of  modern 
times.  He  has  put  the  essence  of  saintliness  into  good  literature 
and  sober  history."  —  Pall  Mall  Gazette. 

"  We  have  no  hesitation  in  saying  that  this  work  will  live  as  one 
of  the  greatest  biographies  in  the  English  language.'"—  The  Daily 
Chronicle.  London. 

"  No  one  can  read  this  remarkable  book  with  its  detailed  descrip- 
tion of  brave  and  unflagging  work  without  endorsing  so  fine  a  tribute. 
There  are  portraits  in  these  volumes,  and  the  work,  apart  from  its 
fascmation  as  a  biography,  throws  a  flood  of  life  on  the  manner  in 
which  Florence  Nightingale  lifted  nursing  from  a  despised  calling  to 
one  of  the  most  honorable  vocations  open  to  modern  womanhood." 
—  The  Standard,  London. 

The  Life  of  Florence  Nightingale 

By  SARAH  A.  TOOLEY 

Author  of  "  Personal  Life  of  Queen  Victoria,"  etc.    With  twenty-two 
Illustrations. 

Cloth,  i2mo,  $i.7S 

In  writing  this  book  the  author  has  had  the  assistance  of  many  of 
Miss  Nightingale's  closest  associates  during  her  active  years,  and  has 
produced  a  singularly  interesting  volume  that  reflects  Miss  Nightin- 
gale's character  and  personality  in  the  happiest  way. 


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Publishers  64-66  Fifth  Avenue  New  York 


"  We  have  no  hesitation  in  saying  that  this  work  will  live  as  one  of  the  greatest 
biographies  in  the  English  language." — The  Daily  Chronicle,  London. 


The  Life  of  Florence  Nightingale 


By  sir  EDWARD  COOK, 

WITH  PHOTOGRAVURE  PORTRAITS 

Cloth,  Svo,  $7.50         carriage  extra 

TWO  VOLUMES 

"This  book,"  says  the  author  in  his  Introductory  remarks  to  this  notable  biography, 
"is  not  a  history  of  the  Crimean  War,  nor  of  nursing,  nor  of  Indian  administration. 
Something  on  all  these  matters  will  be  found  in  it;  but  only  so  much  of  detail  as  was 
necessary  to  place  Miss  Nightingale's  work  in  its  true  light  and  to  exhibit  her  charac- 
teristic methods.  So,  also,  many  other  persons  will  pass  across  the  stage — persons 
drawn  from  many  different  classes,  occupations,  walks  in  life;  but  the  book  does  not 
aim  at  giving  a  detailed  picture  of  'Miss  Nightingale's  circle.'  Her  relations,  her 
friends,  her  acquaintances,  her  correspondents  only  concern  us  here  in  so  far  as  their 
dealings  with  her  affected  her  work,  or  illustrate  her  character." 

The  biography  is  in  two  volumes  and  is  divided  into  seven  Parts.  Part  I  tells  the  story 
of  Florence  Nightingale's  early  years  and  her  early  aspirations  for  a  Hfe  of  active  use- 
fulness. Part  II  is  devoted  to  the  Crimean  War,  where  it  was  as  Administrator  and 
Reformer  rather  than  as  the  Ministering  Angel — the  Lady  With  the  Lamp — that  her 
peculiar  powers  were  shown.  Part  III  portrays  her  laying  her  plans  for  the  health  of 
the  British  Soldier — the  period  of  her  close  co-operation  with  Sidney  Herbert.  Part  IV 
describes,  as  its  main  themes,  the  work  she  did  as  Hospital  Reformer  and  the  Founder 
of  Modern  Nursing.  Part  V  deals  with  a  new  interest  in  her  life  and  a  new  sphere  of 
her  work.  Her  efforts  on  behalf  of  the  British  soldier  at  home  led  to  a  like  attempt  for 
the  army  in  India.  Then  gradually  she  was  drawn  into  other  questions,  till  she  became 
a  keen  Indian  reformer  all  along  the  line.  Part  VI  continues  this  subject,  and  intro- 
duces another  sphere  in  which  her  influence  had  important  significance,  namely,  the 
reform  of  the  Workhouse  Nursing;  and  as  one  thing  led  to  another  it  will  be  seen  that 
Florence  Nightingale  deserves  also  to  be  remembered  as  a  Poor  Law  Reformer.  Part 
VII  comprises  the  last  thirty-eight  years  of  her  life — a  period  which,  though  it  has 
admitted  of  more  summary  treatment,  was  full  of  interest.  It  deals  with  her  literary 
work  and  her  studies  in  Plato  and  Christian  Mystics.  An  endeavor  is  made  to  portray 
her  as  the  "'Mother-Chief"  (as  she  was  called)  of  the  nurses.  It  describes  other  of  her 
projects  and  realizations,  and  so  brings  the  long  and  wonderful  life  to  a  close. 
It  should  be  pointed  out  that  for  the  purposes  of  this  work  Sir  Edward  Cook  has  had 
access  to  the  family  papers,  and  has  therefore  been  able  to  prepare  the  first  full  and 
authentic  record  of  Florence  Nightingale's  character  and  career.  The  volumes  are 
rendered  additionally  attractive  by  the  inclusion  of  several  interesting  portraits. 

PRESS  COMMENTS 

"A  masterly  biography  which  not  only  puts  into  a  permanent  record  her  whole-souled 
devotion  and  humanity,  but  relates  the  history  of  one  of  the  greatest  and  most  fruitful 
movements  of  modern  time.  For  as  Sir  Edward  well  says,  her  nursing  mission  in  the 
Crimean  War  was  only  thfe  starting  point.  .  .  . 

"He  has  put  the  essence  of  saintliness  into  good  literature  and  sober  history." — The 
Pall  Mall  Gazette. 

''.\  noble  biography." — The  Daily  News,  London. 

"A  book  of  surpassing  charm,  worthy  of  the  theme;  in  fine,  a  great  biography  of  a  great 
woman.  ...  A  wonderful  life-story  of  Florence  Nightingale." — The  Daily  Chronicle, 
London. 

"No  one  can  read  this  remarkable  book  with  its  detailed  description  of  brave  and  un- 
flagging work  without  endorsing  so  fine  a  tribute.  There  are  portraits  in  these  volumes, 
and  the  work,  apart  from  its  fascination  as  a  biography,  throws  a  flood  of  light  on  the 
manner  in  which  Florence  Nightingale  lifted  nursing  from  a  despised  calling  to  one  of 
the  most  honourable  vocations  open  to  modern  womanhood." — The  Standard,  London, 


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